Consumer medicine information

Clopidogrel APOTEX Tablets

Clopidogrel

BRAND INFORMATION

Brand name

Clopidogrel APOTEX

Active ingredient

Clopidogrel

Schedule

What is in this leaflet

This leaflet answers some common questions about this medicine. It does not contain all the available information. It does not take the place of talking to your doctor or pharmacist.

All medicines have risks and benefits. Your doctor has weighed the risks of you taking this medicine against the benefits they expect it will have for you.

If you have any concerns about taking this medicine, ask your doctor or pharmacist.

Keep this leaflet with the medicine. You may need to read it again.

What this medicine is used for

Clopidogrel APOTEX contains the active ingredient clopidogrel (as besilate).

Clopidogrel belongs to a group of medicines known as antiplatelet medicines.

Antiplatelet medicines prevent the clumping of very small blood cells (platelets) to reduce the chances of blood clots forming.

Clopidogrel is used to prevent blood clots forming in hardened blood vessels as they can lead to events such as stroke, heart attack or death.

You may have been prescribed clopidogrel because you have:

previously suffered a heart attack, stroke, or have a condition known as peripheral arterial disease (leg pain on walking or at rest)
suffered acute coronary syndrome (either a severe type of chest pain called unstable angina, or a heart attack) – in this case you may also be prescribed aspirin

Ask your doctor if you have any questions about why this medicine has been prescribed for you. Your doctor may have prescribed this medicine for another reason.

There is no evidence that this medicine is addictive.

This medicine is available only with a doctor's prescription.

This medicine should not be used in children.

Before you take this medicine

When you must not take it

Do not take this medicine if you have an allergy to:

any medicine containing clopidogrel
other antiplatelet medicines (such as ticlopidine or prasugrel)
any of the ingredients listed at the end of this leaflet

Some of the symptoms of an allergic reaction may include:

shortness of breath
wheezing or difficulty breathing
swelling of the face, lips, tongue or other parts of the body
rash, itching or hives on the skin

Do not take this medicine if you have any of the following:

medical conditions that cause bleeding such as a stomach ulcers or bleeding within your head
severe liver disease

Do not take this medicine if you are pregnant. It may affect your developing baby if you take it during pregnancy.

Do not breastfeed if you are taking this medicine. Clopidogrel passes into breast milk and there is a possibility that your baby may be affected.

Do not take this medicine after the expiry date printed on the pack or if the packaging is torn or shows signs of tampering. If it has expired or is damaged, return it to your pharmacist for disposal.

If you are not sure whether you should start taking this medicine, talk to your doctor.

Before you start to take it

Tell your doctor if you have allergies to any other medicines, foods, preservatives or dyes.

Tell your doctor if you have or have had any of the following medical conditions:

bleeding disorders or blood clotting problems
any illness or disability that was caused by bleeding e.g. impaired sight or vision because of bleeding within the eye
recent serious injury
recent surgery (including dental surgery)
liver or kidney problems
a genetic condition which means that a certain enzyme (CYP2C19) in your liver works differently and can negatively affect the amount of clopidogrel converting into its active form, resulting in reduced effects (your doctor may perform a test for this condition and depending on results may change your dose or consider an alternative treatment option)
galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption
allergies to other antiplatelet medicines (such as allergic to other antiplatelet medicines (such as ticlopidine, prasugrel
rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption

Tell your doctor if you are pregnant or plan to become pregnant or are breastfeeding. Your doctor can discuss with you the risks and benefits involved.

Tell your doctor if you are planning to have an operation (including dental surgery). Your doctor will decide whether you need to stop clopidogrel prior to surgery.

If you have not told your doctor about any of the above, tell them before you start taking this medicine.

Some patients may not convert clopidogrel to its active form as well as other patients. These patients may not get the same benefit from clopidogrel. Your doctor may advise you to go for tests to determine if clopidogrel will adequately work for you. Based on the test results, your doctor may change your dose of clopidogrel or consider alternative treatments for you.

Taking other medicines

Tell your doctor or pharmacist if you are taking any other medicines, including any that you get without a prescription from your pharmacy, supermarket or health food shop.

Some medicines may interact with clopidogrel. These include:

medicines used to treat or prevent blood clots e.g. aspirin, heparins, warfarin, ticlopidine and prasugrel
non-steroidal anti-inflammatory drugs (NSAIDs), used to treat arthritis, period pain, inflammation, aches and pain
medicines used to treat stomach ulcers, reflux disease (also called heartburn) or prevent gastric reflux e.g. proton-pump inhibitors (such as omeprazole or esomeprazole) or cimetidine
some medicines used to treat infections e.g. ciprofloxacin, chloramphenicol, fluconazole, rifampicin, and voriconazole
medicines used to treat epilepsy e.g. phenytoin, carbamazepine and oxcarbazepine
some antidepressants e.g. fluoxetine, fluvoxamine and moclobemide
some medicines used to treat diabetes e.g. tolbutamide and repaglinide
tamoxifen or paclitaxel, used to treat breast cancer
fluvastatin, used to lower cholesterol
certain types of pain relief medicines called opiates.

These medicines may be affected by clopidogrel or may affect how well it works. You may need different amounts of your medicines, or you may need to take different medicines.

Your doctor and pharmacist have more information on medicines to be careful with or avoid while taking this medicine.

How to take this medicine

Follow all directions given to you by your doctor or pharmacist carefully. They may differ from the information contained in this leaflet.

If you do not understand the instructions on the label, ask your doctor or pharmacist for help.

How much to take

The usual dose of clopidogrel is one 75 mg tablet daily.

If you have acute coronary syndrome, you may receive a single starting dose of 300 mg (four 75 mg tablets) and then continue at one 75 mg tablet daily.

How to take it

Swallow the tablet with a glass of water.

Do not crush or chew the tablets.

When to take it

Take your medicine at about the same time each day. Taking it at the same time each day will have the best effect. It will also help you remember when to take it.

It does not matter if you take this medicine before or after food.

How long to take it for

Continue taking your medicine for as long as your doctor tells you.

This medicine helps to control your condition but does not cure it. It is important to keep taking your medicine even if you feel well.

If you forget to take it

If it is almost time to take your next dose, skip the dose you missed and take your next dose when you are meant to.

Otherwise, take it as soon as you remember, and then go back to taking your medicine as you would normally.

Do not take a double dose to make up for the dose that you missed. This may increase the chance of you getting an unwanted side effect.

If you are not sure what to do, ask your doctor or pharmacist.

If you have trouble remembering to take your medicine, ask your pharmacist for some hints.

If you take too much (overdose)

Immediately telephone your doctor or the Poisons Information Centre (telephone 13 11 26) for advice or go to Accident and Emergency at the nearest hospital, if you think that you or anyone else may have taken too much of this medicine. Do this even if there are no signs of discomfort or poisoning. You may need urgent medical attention.

If you take too much clopidogrel, you may experience excessive bleeding.

While you are taking this medicine

Things you must do

If you are about to be started on any new medicine, remind your doctor and pharmacist that you are taking this medicine.

Tell any other doctors, dentists, and pharmacists who treat you that you are taking this medicine.

If you are going to have surgery, tell the surgeon or anaesthetist that you are taking this medicine. Clopidogrel may increase the risk of bleeding during an operation or some dental work. It may also affect other medicines used during surgery.

If you become pregnant or start to breastfeed while taking this medicine, tell your doctor immediately.

If you are about to have any blood tests, tell your doctor that you are taking this medicine. It may interfere with the results of some tests.

Keep all your doctor's appointments so that your progress can be checked. Your doctor may do some tests from time to time to make sure the medicine is working and to prevent unwanted side effects.

Ask your doctor whether there are any activities you should avoid while taking clopidogrel, for example certain sports. Sometimes after an injury, bleeding may occur inside your body without you knowing about it.

Tell your doctor immediately if you are injured while taking clopidogrel.

Tell your doctor immediately if you notice any of the following:

abnormal bruising or bleeding
abnormal nose bleeds
bloody or black bowel motions
red or purple blotches on your skin
swelling of the face, lips, mouth, tongue or throat which may cause difficulty swallowing or breathing

It may take longer than usual to stop bleeding while you are taking clopidogrel.

Things you must not do

Do not take this medicine to treat any other complaints unless your doctor tells you to.

Do not give your medicine to anyone else, even if they have the same condition as you.

Do not stop taking your medicine or lower the dosage without checking with your doctor.

Things to be careful of

Be careful while driving or operating machinery until you know how clopidogrel affects you.

As with other medicines, clopidogrel may cause faintness or dizziness in some people.

Make sure you know how you react to the medicine before you drive a car or operate machinery or do anything else that could be dangerous if you are faint or dizzy. If this occurs, do not drive.

Be careful when drinking alcohol while you are taking this medicine. If you drink alcohol, faintness or dizziness may be worse.

Side effects

Tell your doctor or pharmacist as soon as possible if you do not feel well while you are taking this medicine.

All medicines can have side effects. Sometimes they are serious but most of the time they are not.

Do not be alarmed by the following lists of side effects. You may not experience any of them.

Tell your doctor if you notice any of the following and they worry you:

diarrhoea
itching
pain or stiffness in the joints
things taste different
flushing
a fast, pounding heart beat

The above list includes the more common side effects of your medicine.

Tell your doctor as soon as possible if you notice any of the following:

(NOTE: If you take both clopidogrel and aspirin, the risk of side effects related to bleeding may be increased.)

bloody or black bowel motions
diarrhoea with blood, mucus, stomach pain and fever
abdominal or stomach pain
vomiting of blood or vomit that looks like coffee grounds
coughing up blood
blood in the eyes
blood in the urine
unusually heavy bleeding or oozing from cuts or wounds
bleeding (including nose bleeds) or bruising more easily than normal
unusually heavy or unexpected menstrual bleeding
numbness (paralysis) or problems with co-ordination
breast enlargement in men
nausea or vomiting
headache (severe and continuing)
faintness or dizziness
light-headedness or blurred vision
slurred speech or other difficulty in speaking
confusion or hallucinations
fever or other signs of infection, such as a sore throat
rash or hives
chills, sweating or clammy skin
fever, muscle weakness, loss of appetite and fatigue
muscle pain
weight loss
anaemia (being tired and looking pale)
red or purple spots visible through your skin
itching, inflamed, cracking or red skin
tightness of the chest, wheezing, coughing or difficulty breathing
yellowing of the skin or the whites of the eyes, pale stools and dark urine with vomiting and stomach pain
symptoms of low blood sugar (hypoglycaemia), including hunger, trembling, feeling weak

The above list includes serious side effects that may require medical attention.

If any of the following happen, tell your doctor immediately or go to Accident and Emergency at your nearest hospital:

symptoms of an allergic reaction including cough, shortness of breath, wheezing or difficulty breathing; swelling of the face, lips, tongue, throat or other parts of the body; rash, itching or hives on the skin

Tell your doctor or pharmacist if you notice anything that is making you feel unwell.

Other side effects not listed above may also occur in some people.

Some of these side effects, such as changes in your blood count, can only be found when your doctor does tests from time to time to check your progress.

Storage and Disposal

Storage

Keep this medicine in its original packaging until it is time to take it. If you take your medicine out of its original packaging it may not keep well.

Keep this medicine in a cool dry place where the temperature will stay below 25°C.

Do not store this medicine, or any other medicine, in the bathroom or near a sink. Do not leave it on a window sill or in the car. Heat and dampness can destroy some medicines.

Keep it where children cannot reach it. A locked cupboard at least one-and-a-half metres above the ground is a good place to store medicines.

Disposal

If your doctor tells you to stop taking this medicine or the expiry date has passed, ask your pharmacist what to do with any medicine that is left over.

Product description

What Clopidogrel APOTEX looks like

Clopidogrel 75 mg tablets
Pink coloured, round biconvex film coated with a smooth surface. AUST R 162329.

Available in blister packs of 28 tablets.

Ingredients

Each tablet contains 75 mg of clopidogrel (as besilate).

It also contains the following inactive ingredients:

mannitol
microcrystalline cellulose
colloidal anhydrous silica
stearic acid
hypromellose
titanium dioxide
iron oxide red

This medicine does not contain lactose, sucrose, gluten, tartrazine or any other azo dyes.

Distributor

Apotex Pty Ltd
16 Giffnock Avenue
Macquarie Park NSW 2113

APOTEX is a registered trademark of Apotex Inc.

This leaflet was last updated in February 2021.

Published by MIMS April 2021

BRAND INFORMATION

Brand name

Clopidogrel APOTEX

Active ingredient

Clopidogrel

Schedule

1 Name of Medicine

Clopidogrel.

2 Qualitative and Quantitative Composition

Clopidogrel APOTEX film coated tablets contain the active ingredient clopidogrel (as besilate).
Each Clopidogrel APOTEX film coated tablet contains 75 mg of clopidogrel (as besilate).
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Clopidogrel APOTEX 75 mg tablets are pink coloured, round biconvex film coated with a smooth surface.

4 Clinical Particulars

4.1 Therapeutic Indications

Prevention of vascular ischaemia associated with atherothrombotic events (myocardial infarction, stroke and vascular death) in patients with a history of symptomatic atherosclerotic disease.

Acute coronary syndrome.

Clopidogrel is indicated in combination with aspirin for patients with:
Unstable angina or non-ST-elevation myocardial infarction in order to prevent early and long-term atherothrombotic events (myocardial infarction, stroke, vascular death or refractory ischaemia). Clopidogrel is indicated for the treatment of acute coronary syndrome whether or not patients undergo cardiac revascularisation (surgical or PCI, with or without stent).
ST-segment elevation acute myocardial infarction in order to prevent atherothrombotic events. In this population, clopidogrel has been shown to reduce the rate of death from any cause and the rate of a combined endpoint of death, re-infarction or stroke in medically treated patients eligible for thrombolytic therapy.

4.2 Dose and Method of Administration

Clopidogrel should be taken once a day with or without food.

Adults.

Generally, clopidogrel should be given as a single daily dose of 75 mg.
In patients with acute coronary syndrome:

Unstable angina or non-ST-elevation myocardial infarction.

Clopidogrel treatment should be initiated with a single 300 mg loading dose and then continued long-term at 75 mg once a day (with aspirin 75 mg-325 mg daily).

ST segment elevation acute myocardial infarction.

Clopidogrel treatment should be given as a single daily dose of 75 mg initiated with or without a 300 mg loading dose in combination with aspirin and with or without thrombolytics. Combined therapy should be started as early as possible after symptoms start. The benefit of the combination of clopidogrel with aspirin beyond four weeks has not been studied in this setting. There are no data on the use of a 300 mg loading dose in elderly patients (aged 75 years or more) with ST-segment acute myocardial infarction, as no patients over 75 years old were included in the CLARITY study and no loading dose was used in the COMMIT study.
In patients who have had percutaneous coronary intervention with stent insertion, clopidogrel and aspirin should be continued for as long as is currently recommended in evidence-based guidelines for the type of stent and circumstances of implantation or for as long as otherwise indicated, taking into account the overall atherothrombotic risk profile of the patient.
No dosage adjustment is necessary for either elderly patients or patients with renal impairment, see Section 5.2 Pharmacokinetic Properties.

Pharmacogenetics.

CYP2C19 poor metaboliser status is associated with diminished antiplatelet response to clopidogrel. Although a higher dose regimen in poor metabolisers increases antiplatelet response (see Section 5.2 Pharmacokinetic Properties, Pharmacogenetics), an appropriate dose regimen for this patient population has not been established in clinical outcome trials. Consider alternative treatment or treatment strategies in patients identified as CYP2C19 poor metabolisers.

Children and adolescents.

Safety and efficacy in subjects below the age of 18 have not been established.

4.3 Contraindications

Hypersensitivity to clopidogrel or any of the excipients.
Severe liver impairment.
Active pathological bleeding such as peptic ulcer and intracranial haemorrhage.
Breast-feeding, see Section 4.6 Fertility, Pregnancy and Lactation.

4.4 Special Warnings and Precautions for Use

General.

As with the other antiplatelet agents, clopidogrel prolongs bleeding time and should be used with caution in patients who may be at risk of increased bleeding from trauma, surgery or other pathological conditions and in patients receiving treatment with acetylsalicylic acid, heparin, glycoprotein IIb/IIIa inhibitors, non-steroidal anti-inflammatory drugs (NSAIDs), selective serotonin reuptake inhibitors (SSRIs), or CYP2C19 strong inducers, as follows:
If a patient is to undergo elective surgery and an antiplatelet effect is not desired, clopidogrel should be discontinued at least five days prior to surgery.
If the patient is at high risk of ophthalmic bleeding due to intraocular lesions clopidogrel should be used with extra caution.
Although clopidogrel has shown a lower incidence of gastrointestinal bleeding compared to aspirin in a large controlled clinical trial (CAPRIE), clopidogrel prolongs bleeding and should be used with caution in patients who have lesions with a propensity to bleed (particularly gastrointestinal and intraocular). Drugs that might induce such lesions (such as aspirin and NSAIDs) should be used with caution in patients taking clopidogrel (see Section 4.5 Interactions with Other Medicines and Other Forms of Interactions).
Patients should be told that it may take longer than usual for bleeding to stop when they take clopidogrel (alone or in combination with aspirin), and that they should report any unusual bleeding (site or duration) to their doctor. Patients should inform doctors and dentists that they are taking clopidogrel before any surgery is scheduled and before any new drug is taken.
In patients with recent transient ischaemic attack or stroke who are at high risk of recurrent ischaemic events, the combination of aspirin and clopidogrel has been shown to increase major bleeding. Therefore, such addition should be undertaken with caution outside of clinical situations where the combination has proven to be beneficial.
Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine.

Coronary artery bypass surgery.

When coronary artery bypass surgery is to be performed, clopidogrel should be suspended at least five days before surgery to reduce the risk of bleeding (see Section 4.8 Adverse Effects (Undesirable Effects)).

Pharmacogenetics.

Clopidogrel is a prodrug. Inhibition of platelet aggregation by clopidogrel is mainly due to an active metabolite. The metabolism of clopidogrel to its active metabolite can be impaired by genetic variations in CYP2C19 and by concomitant medications that interfere with CYP2C19. Genetic variants of other CYP450 enzymes may also affect the formation of clopidogrel's active metabolite. In patients who are CYP2C19 poor metabolisers clopidogrel at recommended doses forms less of the active metabolite of clopidogrel and has a smaller effect on platelet function. Poor metabolisers with acute coronary syndrome or undergoing percutaneous coronary intervention treated with clopidogrel at recommended doses may exhibit higher cardiovascular event rates than do patients with normal CYP2C19 function (see Section 5.2 Pharmacokinetic Properties, Pharmacogenetics; Section 5.1 Pharmacodynamic Properties, Clinical trials).
Use of drugs that induce the activity of CYP2C19 would be expected to result in increased drug levels of the active metabolite of clopidogrel and might potentiate the bleeding risk. As a precaution, concomitant use of strong CYP2C19 inducers should be discouraged (see Section 4.5 Interactions with Other Medicines and Other Forms of Interactions).
Tests are available to identify a patient's CYP2C19 genotype; these tests can be used as an aid in determining therapeutic strategy. Although a higher dose regimen in poor metabolisers increases antiplatelet response (see Section 5.2 Pharmacokinetic Properties, Pharmacogenetics), an appropriate dose regimen for this patient population has not been established in clinical outcome trials. Consider alternative treatment or treatment strategies in patients identified as CYP2C19 poor metabolisers (see Section 4.2 Dose and Method of Administration, Pharmacogenetics).

CYP2C19 metabolism.

Since clopidogrel is metabolised to its active metabolite partly by CYP2C19, use of drugs that inhibit the activity of this enzyme would be expected to result in reduced drug levels of the active metabolite of clopidogrel. The clinical relevance of this interaction is uncertain. Concomitant use of strong or moderate CYP2C19 inhibitors (e.g. omeprazole) should be discouraged see Section 5.2 Pharmacokinetic Properties, Pharmacogenetics; Section 4.4 Special Warnings and Precautions for Use. If a proton pump inhibitor is to be used concomitantly with clopidogrel, consider using one with less CYP2C19 inhibitory activity, such as pantoprazole.
Medicinal products that inhibit CYP2C19 include omeprazole and esomeprazole, fluvoxamine, fluoxetine, moclobemide, voriconazole, fluconazole, ticlopidine, ciprofloxacin, cimetidine, carbamazepine, oxcarbazepine and chloramphenicol.

Haematological.

Thrombotic thrombocytopenic purpura (TTP) has been reported very rarely following the use of clopidogrel, sometimes after a short exposure. It is characterised by thrombocytopenia and microangiopathic haemolytic anaemia associated with either neurological findings, renal dysfunction or fever. TTP is a potentially fatal condition requiring prompt treatment, including plasmapheresis (plasma exchange).
Thrombocytopenia, neutropenia, aplastic anaemia and pancytopenia have also been reported very rarely in patients taking clopidogrel (see Section 4.8 Adverse Effects (Undesirable Effects)).
Due to the risk of bleeding and haematological undesirable effects, blood cell count determination and/or other appropriate testing should be promptly considered whenever clinical symptoms suggestive of bleeding arise during the course of treatment. Because of the increased risk of bleeding, the concomitant administration of warfarin with clopidogrel is not recommended.
As with other anti-platelet agents, clopidogrel should be used with caution in patients who may be at risk of increased bleeding from trauma, surgery or other pathological conditions and in patients receiving treatment with aspirin, non-steroidal anti-inflammatory drugs, heparin, glycoprotein IIb/IIIa inhibitors or thrombolytics. Patients should be followed carefully for any signs of bleeding including occult bleeding, especially during the first weeks of treatment and/or after invasive cardiac procedures or surgery.

Acquired haemophilia.

Acquired haemophilia has been reported following use of clopidogrel. In cases of confirmed isolated activated Partial Thromboplastin Time (aPTT) prolongation with or without bleeding, acquired haemophilia should be considered. Patients with a confirmed diagnosis of acquired haemophilia should be managed and treated by specialists and clopidogrel should be discontinued.

Cross-reactivity among thienopyridines.

Patients should be evaluated for history of hypersensitivity to another thienopyridine (such as ticlopidine, prasugrel) since cross-reactivity among thienopyridines has been reported (see Section 4.8 Adverse Effects (Undesirable Effects)). Thienopyridines may cause mild to severe allergic reactions such as rash, angioedema, or haematological reactions such as thrombocytopaenia and neutropaenia. Patients who had developed a previous allergic reaction and/or haematological reaction to one thienopyridine may have an increased risk of developing the same or another reaction to another thienopyridine. Monitoring for cross-reactivity is advised.

Use in hepatic impairment.

Experience is limited in patients with moderate hepatic disease who may have bleeding diatheses. Clopidogrel should therefore be used with caution in this population.
In the CAPRIE study, it was not mandatory to discontinue study medication in the case of an acute outcome event (acute myocardial infarction, ischaemic stroke or lower extremity amputation) and the patients had a favourable outcome as compared to the aspirin group.
In view of the lack of data, clopidogrel cannot be recommended in acute ischaemic stroke (less than 7 days).

Use in renal impairment.

Experience with clopidogrel is limited in patients with severe renal impairment. Therefore, clopidogrel should be used with caution in this population.

Use in the elderly.

No data available.

Paediatric use.

See Section 4.2 Dose and Method of Administration, Children and adolescents.

Effects on laboratory tests.

No data available.

4.5 Interactions with Other Medicines and Other Forms of Interactions

Aspirin.

A pharmacodynamic interaction between clopidogrel and aspirin is possible, leading to increased risk of bleeding. Therefore, concomitant use should be undertaken with caution. However, clopidogrel and aspirin have been administered together for up to one year. Also see Section 4.4 Special Warnings and Precautions for Use, General.

Oral anticoagulants (including warfarin).

The concomitant administration of clopidogrel with warfarin is not recommended since it may increase the intensity of bleeding.

Glycoprotein IIb/IIIa inhibitors.

Clopidogrel should be used with caution in patients who may be at risk of increased bleeding from trauma, surgery or other pathological conditions that receive concomitant glycoprotein IIb/IIIa inhibitors.

Injectable anticoagulants.

A pharmacodynamic interaction between clopidogrel and heparin is possible, leading to increased risk of bleeding. Therefore, concomitant use should be undertaken with caution.

Anti-platelet agents (such as eptifibatide, ticlopidine, tirofiban).

The effects of clopidogrel and other drugs which inhibit platelet aggregation may be additive, leading to an increased risk of bleeding.

Thrombolytics.

The safety of the concomitant administration of clopidogrel, fibrin or non-fibrin specific thrombolytic agents and heparins was assessed in patients with acute myocardial infarction. The incidence of clinically significant bleeding was similar to that observed when thrombolytic agents and heparins are co-administered with aspirin. The safety of concomitant administration of clopidogrel with thrombolytic agents has not been formally established and should be undertaken with caution.

Drugs associated with bleeding risk.

There is an increased risk of bleeding due to the potential additive effect. The concomitant administration of drugs associated with bleeding risk should be undertaken with caution.

Nonsteroidal anti-inflammatory drugs (NSAIDs).

In a clinical study conducted in healthy volunteers, the concomitant administration of clopidogrel and naproxen increased occult gastrointestinal blood loss. However, due to the lack of interaction studies with other NSAIDs, it is presently unclear whether there is an increased risk of gastrointestinal bleeding with all NSAIDs. Consequently, there is a potential increased risk of gastrointestinal bleeding and NSAIDs and clopidogrel should be co-administered with caution (see Section 4.4 Special Warnings and Precautions for Use).

Selective serotonin reuptake inhibitors (SSRIs).

Since SSRIs affect platelet activation and increase the risk of bleeding, the concomitant administration of SSRIs with clopidogrel should be undertaken with caution.

Drugs metabolised by cytochrome P450 2C9.

At high concentrations in vitro, clopidogrel inhibits cytochrome P450 (2C9). Accordingly, Plavix may interfere with the metabolism of phenytoin, tamoxifen, tolbutamide, warfarin, fluvastatin, and many non-steroidal anti-inflammatory agents, but there are no data with which to predict the magnitude of these interactions. Caution should be used when any of these drugs is co-administered with clopidogrel.

Other concomitant therapy.

Inducers of CYP2C19.

Since clopidogrel is metabolised to its active metabolite partly by CYP2C19, use of drugs that induce the activity of this enzyme would be expected to result in increased drug levels of the active metabolite of clopidogrel.
Rifampicin strongly induces CYP2C19, resulting in both an increased level of clopidogrel active metabolite and platelet inhibition, which in particular might potentiate the risk of bleeding. As a precaution, concomitant use of strong CYP2C19 inducers should be discouraged (see Section 4.4 Special Warnings and Precautions for Use).

Inhibitors of CYP2C19.

Since clopidogrel is metabolised to its active metabolite partly by CYP2C19, use of drugs that inhibit the activity of this enzyme would be expected to result in reduced drug levels of the active metabolite of clopidogrel. The clinical relevance of this interaction is uncertain. Concomitant use of strong or moderate CYP2C19 inhibitors (e.g. omeprazole) should be discouraged (see Section 5.2 Pharmacokinetic Properties, Pharmacogenetics; Section 4.4 Special Warnings and Precautions for Use). If a proton pump inhibitor is to be used concomitantly with clopidogrel, consider using one with less CYP2C19 inhibitory activity, such as pantoprazole.
Medicinal products that inhibit CYP2C19 include omeprazole and esomeprazole, fluvoxamine, fluoxetine, moclobemide, voriconazole, fluconazole, ticlopidine, ciprofloxacin, cimetidine, carbamazepine, oxcarbazepine and chloramphenicol.

Proton Pump Inhibitors (PPI).

In a crossover clinical study (N = 72 healthy subjects), clopidogrel (300-mg loading dose followed by 75 mg/day) alone and with omeprazole (80 mg at the same time as clopidogrel) were administered for 5 days. Mean maximal platelet aggregation intensity % (MAI) was the primary pharmacodynamic endpoint of the clinical study and was used in the calculation of the mean inhibition of platelet aggregation % (IPA). Similar trends in results were seen across both the MAI% and IPA%. The exposure to the active metabolite of clopidogrel was decreased by 45% (Day 1) and 40% (Day 5) when clopidogrel and omeprazole were administered together. Mean inhibition of platelet aggregation with 5 microM ADP was diminished by 39% (24 hours) and 21% (Day 5) when clopidogrel and omeprazole were administered together. The same results were observed when omeprazole 80 mg was administered 12 hours apart.
In a crossover clinical study (N = 66), healthy subjects were administered clopidogrel (300-mg loading dose followed by 75 mg/day) alone and with pantoprazole (80 mg at the same time as clopidogrel) for 5 days. Mean maximal platelet aggregation intensity % was the primary pharmacodynamic endpoint of the clinical study and was used in the calculation of the mean inhibition of platelet aggregation %. Similar trends in results were seen across both the MAI% and IPA%. The exposure to the active metabolite of clopidogrel was decreased by 20% (Day 1) and 14% (Day 5) when clopidogrel and pantoprazole were administered together. Mean inhibition of platelet aggregation was diminished by 15% (24 hours) and 11% (Day 5) when clopidogrel and pantoprazole were administered together. These results indicate that clopidogrel can be administered with pantoprazole.
Inconsistent data on the clinical implications of this pharmacokinetic (PK)/pharmacodynamic (PD) interaction in terms of major cardiovascular events have been reported from both observational and clinical studies.
A number of other clinical studies have been conducted with clopidogrel and other concomitant medications to investigate the potential for pharmacodynamic and pharmacokinetic interactions. No clinically significant pharmacodynamic interactions were observed when clopidogrel was co-administered with atenolol, nifedipine, or both atenolol and nifedipine. Furthermore, the pharmacodynamic activity of clopidogrel was not significantly influenced by the co-administration of phenobarbital, or oestrogen.
In a study comparing administration of warfarin with either clopidogrel (N = 20) or placebo (N = 23) the administration of clopidogrel 75 mg/day for 8 days did not modify the pharmacokinetics of S-warfarin (a CYP2C9 substrate) or INR in patients receiving long-term warfarin therapy (at least 2 months). Coadministration of clopidogrel with warfarin increases the risk of bleeding because of independent effects on hemostasis. However, at high concentrations in vitro, clopidogrel inhibits CYP2C9. It is unlikely that clopidogrel interferes with the metabolism of drugs such as phenytoin and tolbutamide and the NSAIDs, which are metabolised by cytochrome P450 2C9. Data from the CAPRIE study indicate that phenytoin and tolbutamide can be safely co-administered with clopidogrel.
The pharmacokinetics of digoxin or theophylline were not modified by the co-administration of clopidogrel. Antacids did not modify the extent of clopidogrel absorption.

CYP2C8 substrate drugs.

Clopidogrel has been shown to increase repaglinide exposure in healthy volunteers. In vitro studies have shown the increase in repaglinide exposure is due to inhibition of CYP2C8 by the glucuronide metabolite of clopidogrel. Due to the risk of increased plasma concentrations, concomitant administration of clopidogrel and drugs primarily cleared by CYP2C8 metabolism (e.g. repaglinide, paclitaxel) should be undertaken with caution.
In addition to the above specific interaction studies, patients entered into clinical trials with clopidogrel (including CAPRIE, CURE, CLARITY and COMMIT) received a variety of concomitant medications including diuretics, beta-blocking agents, angiotensin converting enzyme inhibitors, calcium antagonists, cholesterol lowering agents, coronary vasodilators, anti-diabetic agents (including insulin), anti-epileptic agents, GPIIb/IIIa antagonists and hormone replacement therapy without evidence of clinically significant adverse interactions.
As with other oral P2Y12 inhibitors, co-administration of opioid agonists has the potential to delay and reduce the absorption of clopidogrel presumably because of slowed gastric emptying. The clinical relevance is unknown. Consider the use of a parenteral antiplatelet agent in acute coronary syndrome patients requiring co-administration of morphine or other opioid agonists.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

Clopidogrel was found to have no effect on fertility of male and female rats at oral doses up to 400 mg/kg per day and was not teratogenic in rats (up to 500 mg/kg per day) and rabbits (up to 300 mg/kg per day).
(Category B1)
Clopidogrel and/or its metabolites are known to cross the placenta in pregnant rats and rabbits. However, teratology studies in rats and rabbits at doses up to 500 mg and 300 mg/kg/day PO, respectively, revealed no evidence of embryotoxicity or teratogenicity. There are no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of a human response, clopidogrel should not be used in women during pregnancy.
Studies in rats have shown that clopidogrel and/or its metabolites are excreted in breast milk (see Section 4.3 Contraindications).

4.7 Effects on Ability to Drive and Use Machines

No impairment of driving or psychometric performance was observed following clopidogrel administration.

4.8 Adverse Effects (Undesirable Effects)

Clinical studies experience.

Clopidogrel has been evaluated for safety in more than 42,000 patients, including over 9,000 patients treated for 1 year or more. The clinically relevant adverse events observed in CAPRIE, CURE, CLARITY and COMMIT are discussed below.
Clopidogrel was well tolerated compared to aspirin in a large controlled clinical trial (CAPRIE). The overall tolerability of clopidogrel in this study was similar to aspirin, regardless of age, gender and race.

Haemorrhagic disorders.

In CAPRIE, the overall incidence of any bleeding in patients treated with either clopidogrel or aspirin was similar (9.3%). The incidence of severe bleeds was 1.4% in the clopidogrel group and 1.6% in the aspirin group.
Gastrointestinal haemorrhage was significantly less frequent with clopidogrel (1.99%) compared to aspirin (2.66%). The incidence of intracranial haemorrhage was 0.35% for clopidogrel compared to 0.49% for aspirin.
In CURE, there was a significant difference between the two treatment groups for non life-threatening major bleeds (1.6% clopidogrel + aspirin vs. 1.0% placebo + aspirin), primarily gastrointestinal and at puncture sites, and minor bleeds (5.1% clopidogrel + aspirin vs. 2.4% placebo + aspirin). The major bleeding event rate for clopidogrel + aspirin was dose-dependent on aspirin (< 100 mg: 2.6%; 100-200 mg: 3.5%; > 200 mg: 4.9%) as was the major bleeding event rate for placebo + aspirin (< 100 mg: 2.0%; 100-200 mg: 2.3%; > 200 mg: 4.0%).
The administration of clopidogrel + aspirin as compared to placebo + aspirin, was not associated with an increase in life-threatening or fatal bleeds (event rates 2.2% vs. 1.8% and 0.2% vs. 0.2%, respectively). The incidence of intra-cranial bleeding was 0.1% in both groups.
There was no excess in major bleeds within 7 days after coronary bypass graft surgery in patients who stopped therapy more than five days prior to surgery (4.4% clopidogrel + aspirin vs. 5.3% placebo + aspirin). In patients who remained on therapy within five days of bypass graft surgery, the event rate was 9.6% for clopidogrel + aspirin, and 6.3% for placebo + aspirin.
In CLARITY, there was an overall increase in bleeding in the clopidogrel + aspirin group (17.4%) versus the placebo + aspirin group (12.9%), with the incidence of major bleeding (defined as intracranial bleeding or bleeding associated with a fall in haemoglobin > 5 g/dL) being similar between groups (1.3% versus 1.1% in the clopidogrel + aspirin and the placebo + aspirin groups, respectively). This was consistent across subgroups of patients defined by baseline characteristics, and type of fibrinolytics or heparin therapy. The incidence of fatal bleeding (0.8% versus 0.6% in the clopidogrel + aspirin and in the placebo + aspirin groups, respectively) and intracranial haemorrhage (0.5% versus 0.7%, respectively) was low and similar in both groups.
The overall rate of major bleeding in COMMIT was low and similar in both groups, as shown in Table 1.

In CHARISMA, a study conducted in a broad patient population including patients with prior documented coronary artery disease, cerebrovascular disease or peripheral arterial disease as well as patients with a combination of atherothrombotic risk factors only, all receiving a background therapy with low dose aspirin (75-162 mg), there was an excess in moderate and severe bleeding, as adjudicated to the GUSTO definitions, in the clopidogrel group. This represented a number needed to treat, to harm, of 84 in 23 months of follow-up. See Table 2.

Haematological disorders.

In CAPRIE, patients were intensively monitored for thrombocytopenia and neutropenia.
Clopidogrel was not associated with an increase in the incidence of thrombocytopenia compared to aspirin. Very rare cases of platelet count < 30 x 10⁹/L have been reported.
Aplastic anaemia has occurred whilst on clopidogrel treatment.
Severe neutropenia (< 0.45 x 10⁹/L) was observed in four patients (0.04%) that received clopidogrel and in two patients that received aspirin. Two of the 9599 patients who received clopidogrel and none of the patients who received aspirin had a neutrophil count of zero. One of the clopidogrel treated patients was receiving cytostatic chemotherapy, and another recovered and returned to the trial after only temporarily interrupting treatment with clopidogrel.
In CURE and CLARITY, the numbers of patients with thrombocytopenia or neutropenia were similar in both groups.
Although the risk of myelotoxicity with clopidogrel appears to be quite low, this possibility should be considered when a patient receiving clopidogrel demonstrates fever or other signs of infection.

Gastrointestinal.

In CAPRIE, overall the incidence of gastrointestinal events (e.g. abdominal pain, dyspepsia, gastritis and constipation) in patients receiving clopidogrel was significantly lower than in those receiving aspirin. The incidence of peptic, gastric, or duodenal ulcers was 0.68% for clopidogrel and 1.15% for aspirin. Cases of diarrhoea were reported at a higher frequency in the clopidogrel group (4.46%) compared to the aspirin group (3.36%).
In CURE, there was no significant difference in the incidence of non-haemorrhagic gastrointestinal effects in the clopidogrel or placebo groups.
In CLARITY, the incidence of gastrointestinal adverse events was 6.9% for clopidogrel treated patients, compared to 7.2% in placebo treated patients.
In COMMIT, 2 patients reported gastrointestinal adverse events in the clopidogrel treated group, compared to one in the placebo treated group.

Rash.

In CAPRIE, there were significantly more patients with rash in the clopidogrel group (4.2%) compared to the aspirin group (3.5%). In CURE, rash occurred in more patients in the clopidogrel group. In CLARITY, 0.7% of patients in the clopidogrel group reported a rash, compared to 0.5% in the placebo group.

Treatment discontinuation.

In the clopidogrel and aspirin treatment groups of the CAPRIE study, discontinuation due to adverse events occurred in approximately 13% of patients after 2 years of treatment. Adverse events occurring in ≥ 2.5% of patients on clopidogrel in the CAPRIE controlled clinical trial are shown in Table 3 regardless of relationship to clopidogrel. The median duration of therapy was 20 months, with a maximum of 3 years.
In CURE, the overall incidence of discontinuation due to adverse events was greater in the clopidogrel group than in the placebo group (366 [5.8%] and 247 [3.9%] patients, respectively), with the main differences being in events in the platelet, bleeding and clotting disorders (1.1% versus 0.7%) and skin disorders (0.7% versus 0.3%). The increase in the rate of study drug discontinuation due to non-haemorrhagic adverse events was primarily due to the increase in rash seen in the clopidogrel group. There was no apparent difference between the 2 treatment groups in the rates of discontinuations due to other adverse events.
In CLARITY, the overall incidence of discontinuation due to adverse events was greater in the placebo group compared with the clopidogrel group (6.9% for clopidogrel treated patients compared to 8.6% for placebo treated patients).
In COMMIT, the overall incidence of discontinuation due to adverse events was similar in each treatment group (2.4% for clopidogrel treated patients compared to 2.2% for placebo treated patients).

Clinically relevant adverse reactions not listed above pooled from CAPRIE, CURE, CLARITY and COMMIT studies with an incidence of ≥ 0.1% as well as all serious and clinically relevant adverse reactions are listed below according to the World Health Organisation classification.
Their frequency is defined using the following conventions: common: > 1/100 (1%) and < 1/10 (10%); uncommon: ≥ 1/1000 (0.1%) and < 1/100 (1%) and rare: ≥ 1/10,000 (0.01%) and < 1/1000 (0.1%).

Central and peripheral nervous system disorders.

Uncommon: Paraesthesia, headache, dizziness.
Rare: Vertigo.

Gastrointestinal system disorders.

Common: Dyspepsia, abdominal pain, diarrhoea.
Uncommon: Flatulence, nausea, gastritis, constipation, vomiting, gastric, peptic or duodenal ulcer.

Platelet, bleeding and clotting disorders.

Uncommon: Bleeding time increased, platelets decreased.

Skin and appendages disorders.

Uncommon: rash, pruritus.

White cell and RES disorders.

Uncommon: Leucopenia, neutrophils decreased and eosinophilia.

Post-marketing experience.

The following have been reported spontaneously from worldwide post-marketing experience:
Note: very common ≥ 1/10 (≥ 10%), common ≥ 1/100 and < 1/10 (≥ 1% and < 10%), uncommon ≥ 1/1000 and < 1/100 (≥ 0.1% and < 1.0%), rare ≥ 1/10,000 and < 1/1000 (≥ 0.01% and < 0.1%), very rare < 1/10,000 (< 0.01%), Not known cannot be estimated from available data.

Musculoskeletal, connective and bone.

Very rare: Arthralgia, arthritis, myalgia.

Immune system disorders.

Very rare: anaphylactoid reactions, serum sickness.
Uncommon: cross-reactive hypersensitivity among thienopyridine (such as ticlopidine, prasugrel) (see Section 4.4 Special Warnings and Precautions for Use).
Not known: Insulin autoimmune syndrome, which can lead to severe hypoglycaemia, particularly in patients with HLA DR A4 subtype (more frequent in the Japanese population).

Cardiac disorders.

Kounis syndrome (vasospastic allergic angina/allergic myocardial infarction) in the context of a hypersensitivity reaction due to clopidogrel.

Vascular disorders.

Very rare: vasculitis, hypotension.

Blood and lymphatic system disorders.

Very rare: serious cases of bleeding, mainly skin, musculo-skeletal (haemarthrosis, haematoma), eye (conjunctival, ocular, retinal) and respiratory tract bleeding (haemoptysis, pulmonary haemorrhage), epistaxis, haematuria and haemorrhage of operative wound. Fatal haemorrhage, including intracranial, gastrointestinal and retroperitoneal haemorrhage. Cases of serious haemorrhage have been reported in patients taking clopidogrel concomitantly with aspirin or clopidogrel with aspirin and heparin (see Section 4.5 Interactions with Other Medicines and Other Forms of Interactions).
Very rare cases of thrombotic thrombocytopenic purpura (TTP), have been reported.
Very rare cases of acquired haemophilia A have been reported.
Very rare: aplastic anaemia, neutropenia, pancytopenia, agranulocytosis, granulocytopenia, anaemia.
Uncommon: eosinophilia, leucopenia, decreased neutrophils, decreased platelets, increased bleeding time.

Skin and subcutaneous tissue disorders.

Very rare: maculopapular, erythematous or exfoliative rash, urticaria, pruritus, angioedema, bullous dermatitis (erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, acute generalised exanthematous pustulosis (AGEP)), drug-induced hypersensitivity syndrome, drug rash with eosinophilia and systemic symptoms (DRESS), eczema, lichen planus.

Psychiatric.

Very rare: confusion, hallucinations.

Nervous system disorders.

Very rare: taste disturbances.
Not known: ageusia.

Hepatobiliary disorders.

Very rare: hepatitis, acute liver failure.

Gastrointestinal disorders.

Very rare: colitis (including ulcerative or lymphocytic colitis), pancreatitis, stomatitis.

Respiratory, thoracic and mediastinal disorders.

Very rare: bronchospasm, interstitial pneumonitis, eosinophilic pneumonia.

Renal and urinary disorders.

Very rare: glomerulopathy.

Reproductive systems and breast disorders.

Very rare: gynaecomastia.

Investigations.

Very rare: blood creatinine increase, abnormal liver function tests.

General disorders and administration site conditions.

Very rare: fever, syncope.

Reporting suspected adverse effects.

Reporting suspected adverse reactions after registration of the medical product is important. It allows continued monitoring of the benefit-risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions at http://www.tga.gov.au/reporting-problems.

4.9 Overdose

In animals, clopidogrel at single oral doses ≥ 1500 mg/kg caused necrotic-haemorrhagic gastritis, oesophagitis and enteritis in mice, rats and baboons. Necrotic tubulopathy and tubulo-interstitial nephritis were also noted in mice.
Overdose following clopidogrel administration may lead to prolonged bleeding time and subsequent bleeding complications. Appropriate therapy should be considered if bleeding is observed. No antidote to the pharmacological activity of clopidogrel has been found. If prompt correction of prolonged bleeding time is required, platelet transfusion may reverse the effects of clopidogrel.
For information on the management of overdose, contact the Poison Information Centre on 131126 (Australia).

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Clopidogrel is a specific and potent inhibitor of platelet aggregation. Platelets have an established role in the pathophysiology of atherosclerotic disease and thrombotic events. Long term use of anti-platelet drugs has shown consistent benefit in the prevention of ischaemic stroke, myocardial infarction and vascular death in patients at increased risk of such outcomes, including those with established atherosclerosis or a history of atherothrombosis.

Mechanism of action.

The active metabolite, a thiol derivative, is formed by oxidation of clopidogrel to 2-oxoclopidogrel and subsequent hydrolysis. The active metabolite of clopidogrel selectively inhibits the binding of ADP to its platelet P2Y12 receptor and the subsequent ADP-mediated activation of the GPIIb/IIIa complex, thereby inhibiting platelet aggregation. Clopidogrel also inhibits platelet aggregation induced by other agonists by blocking the amplification of platelet activation by released ADP. Due to the irreversible binding, platelets exposed are affected for the remainder of their lifespan and recovery of normal platelet function occurs at a rate consistent with platelet turnover (approximately 7 days).
Statistically significant and dose-dependent inhibition of platelet aggregation was noted 2 hours after single oral doses of clopidogrel. Repeated doses of 75 mg per day produced substantial inhibition of ADP-induced platelet aggregation from the first day; this increased progressively and reached steady state between Day 3 and Day 7. At steady state, the average inhibition level observed with a dose of 75 mg per day was between 40% and 60%. Platelet aggregation and bleeding time gradually returned to baseline values, generally within 7 days after treatment was discontinued.

Clinical trials.

The safety and efficacy of clopidogrel in preventing vascular ischaemic events has been evaluated in four double-blind studies: the CAPRIE study, a comparison of clopidogrel to aspirin, and the CURE, CLARITY and COMMIT studies, which compared clopidogrel in combination with aspirin, to placebo with aspirin.

Myocardial infarction or stroke, or established peripheral arterial disease.

The CAPRIE study included 19,185 patients with established atherosclerosis or history of atherothrombosis as manifested by myocardial infarction, ischaemic stroke or peripheral arterial disease. Patients were randomised to clopidogrel 75 mg/day or aspirin 325 mg/day, and were followed for 1 to 3 years.
The trial's primary outcome was the time to first occurrence of new ischaemic stroke (fatal or not), new myocardial infarction (fatal or not), or other vascular death. Deaths not easily attributable to nonvascular causes were all classified as vascular.

As shown in Table 4, clopidogrel was associated with a lower incidence of outcome events of every kind. The overall risk reduction (9.78% vs. 10.64%) was 8.7%, p = 0.045. Similar results were obtained when all-cause mortality and all-cause strokes were counted instead of vascular mortality and ischaemic strokes (risk reduction 6.9%). In patients who survived an on-study stroke or myocardial infarction, the incidence of subsequent events was again lower in the clopidogrel group.
The curves showing the overall event rate are shown in Figure 1. The event curves separated early and continued to diverge over the 3-year follow-up period.

Acute coronary syndrome.

The CURE study included 12,562 patients with acute coronary syndrome (unstable angina or non-ST-elevation myocardial infarction), and presenting within 24 hours of onset of the most recent episode of chest pain or symptoms consistent with ischaemia. Patients were required to have either ECG changes compatible with new ischaemia or elevated cardiac enzymes or troponin I or T to at least twice the upper limit of normal. Patients were randomised to clopidogrel (300 mg loading dose followed by 75 mg/day, n = 6244) or placebo (n = 6287), both given in combination with aspirin (75-325 mg once daily) and other standard therapies (oral anti-coagulants and long term NSAIDs were not permitted). Patients were treated for up to one year.
The number of patients experiencing the primary endpoint [cardiovascular (CV) death, myocardial infarction (MI), or stroke] was 582 (9.3%) in the clopidogrel-treated group and 719 (11.4%) in the placebo-treated group, a 20% relative risk reduction (95% CI of 10%-28%; p = 0.00009) for the clopidogrel-treated group. The benefits of clopidogrel were seen within a few hours and maintained throughout the course of the study (up to 12 months). The primary outcome was reduced to a similar extent within the first 30 days (relative risk reduction of 22%), from 30 days to one year (relative risk reduction of 19%), and for the entire one year study (relative risk reduction of 20%).
The number of patients experiencing the co-primary endpoint (CV death, MI, stroke or refractory ischaemia) was 1035 (16.5%) in the clopidogrel-treated group and 1187 (18.8%) in the placebo-treated group, a 14% relative risk reduction (95% CI of 6%-21%, p = 0.0005) for the clopidogrel-treated group, a benefit which was consistent for each component, indicating that clopidogrel reduced a range of atherothrombotic events.
In the course of the study, patients who underwent cardiac revascularisation (surgical or percutaneous coronary intervention with or without coronary stent implantation), received similar benefit from clopidogrel + aspirin (including standard therapies) as those who did not have a cardiac revascularisation.
The results obtained in populations with different characteristics (e.g. unstable angina or non-ST-elevation MI, low to high risk levels, diabetes, need for revascularisation, age, gender, etc.) were consistent with the results of the primary analysis.
The benefits observed with clopidogrel were independent of other acute and long-term cardiovascular therapies (such as heparin/LMWH, GPIIb/IIIa antagonists, lipid lowering drugs, beta blockers, and ACE-inhibitors). The efficacy of clopidogrel was observed independently of the dose of aspirin (75-325 mg once daily).
In patients with ST-segment elevation acute myocardial infarction, safety and efficacy of clopidogrel have been evaluated in two randomised, placebo-controlled, double-blind studies, CLARITY and COMMIT.
The randomised, double-blind, placebo-controlled CLARITY trial included 3,491 patients presenting within 12 hours of the onset of a ST elevation myocardial infarction and planned for thrombolytic therapy. Patients were randomised to receive either clopidogrel (300 mg loading dose, followed by 75 mg/day; n = 1752) or placebo (n = 1739), together with aspirin (150 to 325 mg loading dose followed by 75 to 162 mg/day), a fibrinolytic agent and, when appropriate, heparin for 48 hours. The patients were followed for 30 days.
The primary endpoint was the occurrence of the composite of an occluded infarct-related artery (defined as TIMI Flow Grade 0 or 1) on the predischarge angiogram, or death or recurrent myocardial infarction by the time of the start of coronary angiography. For patients who did not undergo angiography, the primary endpoint was death or recurrent myocardial infarction by Day 8 or by hospital discharge, if prior to Day 8.
The patient population was mostly Caucasian (89.5%) and included 19.7% women and 29.2% were 65 years or over. A total of 99.7% of patients received fibrinolytics (fibrin specific: 68.7%, non-fibrin specific: 31.1%), 89.5% heparin, 78.7% beta-blockers, 54.7% ACE inhibitors and 63% statins.
The number of patients who reached the primary endpoint was 262 (15.0%) in the clopidogrel-treated group and 377 (21.7%) in the placebo group, representing an absolute reduction of 6.7% and a 36% reduction in the odds of the endpoint in favour of treatment with clopidogrel (95% CI: 0.53, 0.76; p < 0.001), as shown in Table 5, mainly related to a reduction in occluded infarct-related arteries.
The benefit of clopidogrel on the primary endpoint was consistent across all prespecified subgroups, including patients' age, gender, infarct location and type of fibrinolytic or heparin used.

The randomised, double-blind, placebo-controlled, 2x2 factorial design COMMIT trial included 45,852 patients presenting within 24 hours of the onset of the symptoms of suspected myocardial infarction with supporting ECG abnormalities (i.e. ST elevation, ST depression or left bundle-branch block). Patients were randomised to receive clopidogrel (75 mg/day) or placebo, in combination with aspirin (162 mg/day), for 28 days or until hospital discharge, whichever came first.
The co-primary endpoints were death from any cause and the first occurrence of re-infarction, stroke or death. The patient population included 27.8% women, 58.4% 60 years or over (26% 70 years or over) and 54.5% patients who received fibrinolytics, 68% who received ACE-inhibitors and 10.9% who received non-trial beta-blockers (as well as half of the patients who received metoprolol as study medication).
As shown in Table 6 and Figures 2 and 3, clopidogrel significantly reduced the relative risk of death from any cause by 7% (p = 0.029) and the relative risk of the combination of re-infarction, stroke or death by 9% (p = 0.002), representing an absolute risk reduction of 5 and 9 patients per 1000 treated (0.5 and 0.9%), respectively.

The benefit associated with clopidogrel on the combined endpoint was consistent across age, gender and with or without fibrinolytics and was observed as early as 24 hours.

5.2 Pharmacokinetic Properties

Absorption.

After single and repeated oral doses of 75 mg/day, clopidogrel is rapidly absorbed. Mean peak plasma levels of unchanged clopidogrel (approximately 2.2-2.5 nanogram/mL after a single 75 mg oral dose) occurred approximately 45 minutes after dosing. The increase in area under the curve (AUC) in the range of 75 to 300 mg is dose proportional, while the C_max increases by 3-fold for a 4-fold increase in dose. Absorption is at least 50%, based on urinary excretion of clopidogrel metabolites.

Distribution.

Clopidogrel and the main circulating metabolite bind reversibly in vitro to human plasma proteins (98% and 94% respectively). The binding is non saturable in vitro over a wide concentration range.

Metabolism.

Clopidogrel is extensively metabolised by two main metabolic pathways: one mediated by esterases and leading to hydrolysis into an inactive carboxylic acid derivative (85% of circulating metabolites) and one mediated by multiple cytochrome P450 enzymes. Cytochromes first oxidize clopidogrel to a 2-oxo-clopidogrel intermediate metabolite. Subsequent metabolism of the 2-oxo-clopidogrel intermediate metabolite results in formation of the active metabolite, a thiol derivative of clopidogrel. The active metabolite is formed mostly by CYP2C19 with contributions from several other CYP enzymes, including CYP3A4, CYP3A, CYP2B6 and CYP1A2. The active thiol metabolite binds rapidly and irreversibly to platelet receptors, thus inhibiting platelet aggregation for the lifespan of the platelet.
The C_max of the active metabolite is twice as high following a single 300 mg clopidogrel loading dose as it is after four days of 75 mg maintenance dose. C_max occurs approximately 30 to 60 minutes after dosing.

Excretion.

Following an oral dose of 14C-labelled clopidogrel in man, approximately 50% was excreted in the urine and approximately 46% in the faeces in the 120 hour interval after dosing. After a single, oral dose of 75 mg, clopidogrel has a half-life of approximately 6 hours. The half-life of the active metabolite is about 30 minutes.

Pharmacogenetics.

CYP2C19 is involved in the formation of both the active metabolite and the 2-oxo-clopidogrel intermediate metabolite. Clopidogrel active metabolite pharmacokinetics and antiplatelet effects, as measured by ex vivo platelet aggregation assays, differ according to CYP2C19 genotype. Genetic variants of other CYP450 enzymes may also affect the formation of clopidogrel's active metabolite.
The CYP2C19*1 allele corresponds to fully functional metabolism while the CYP2C19*2 and *3 alleles are nonfunctional. CYP2C19*2 and *3 account for the majority of reduced function alleles in white (85%) and Asian (99%) poor metabolisers. Other alleles associated with absent or reduced metabolism are less frequent, and include, but are not limited to, CYP2C19*4, *5, *6, *7, and *8. A patient with poor metaboliser status will possess two loss-of-function alleles as defined above. Published frequencies for poor CYP2C19 metaboliser genotypes are approximately 2% for whites, 4% for blacks and 14% for Chinese and are listed in Table 7. Tests are available to determine a patient's CYP2C19 genotype.

A crossover study in 40 healthy subjects, 10 each in the four CYP2C19 metaboliser groups (ultrarapid, extensive, intermediate and poor), evaluated pharmacokinetic and antiplatelet responses using 300 mg followed by 75 mg/day and 600 mg followed by 150 mg/day, each for a total of 5 days (steady state). No substantial differences in active metabolite exposure and mean inhibition of platelet aggregation (IPA) were observed between ultrarapid, extensive and intermediate metabolisers. In poor metabolisers, active metabolite exposure was decreased by 63-71% compared to extensive metabolisers. After the 300 mg/75 mg dose regimen, antiplatelet responses were decreased in the poor metabolisers with mean IPA (5 microM ADP) of 24% (24 hours) and 37% (Day 5) as compared to IPA of 39% (24 hours) and 58% (Day 5) in the extensive metabolisers and 37% (24 hours) and 60% (Day 5) in the intermediate metabolisers. When poor metabolisers received the 600 mg/150 mg regimen, active metabolite exposure was greater than with the 300 mg/75 mg regimen. In addition, IPA was 32% (24 hours) and 61% (Day 5), which were greater than in poor metabolisers receiving the 300 mg/75 mg regimen, and were similar to the other CYP2C19 metaboliser groups receiving the 300 mg/75 mg regimen. An appropriate dose regimen for this patient population has not been established in clinical outcome trials (see Section 4.2 Dose and Method of Administration).

Consistent with the results (see Table 8), in a meta-analysis including 6 studies of 335 clopidogrel-treated subjects at steady state, it was shown that active metabolite exposure was decreased by 28% for intermediate metabolisers, and 72% for poor metabolisers while platelet aggregation inhibition (5 microM ADP) was decreased with differences in IPA of 5.9% and 21.4%, respectively, when compared to extensive metabolisers.
The influence of CYP2C19 genotype on clinical outcomes in patients treated with clopidogrel has not been evaluated in prospective, randomized, controlled trials. There have, however, been a number of retrospective analyses to evaluate this effect in patients treated with clopidogrel for whom there are genotyping results: CURE (n = 2721), CHARISMA (n = 2428), CLARITY-TIMI 28 (n = 227), and TRITON-TIMI 38 (n = 1477) and ACTIVE-A (n = 601), as well as a number of published cohort studies.
In TRITON TIMI 38 and 3 of the cohort studies (Collet, Sibbing, Giusti) the combined group of patients with either intermediate or poor metaboliser status had a higher rate of cardiovascular events (death, myocardial infarction, and stroke) or stent thrombosis compared to extensive metabolisers.
In CHARISMA and one cohort study (Simon), an increased event rate was observed only in poor metabolisers when compared to extensive metabolisers.
In CURE, CLARITY, ACTIVE-A and one of the cohort studies (Trenk), no increased event rate was observed based on metaboliser status.
None of these analyses were adequately sized to detect differences in outcome in poor metabolisers.

Special populations.

The pharmacokinetics of the active metabolite of clopidogrel is not known in these special populations.

Geriatric patients.

Plasma concentrations of the main circulating metabolite are significantly higher in the elderly (≥ 75 years) compared to young healthy volunteers but these higher plasma levels were not associated with differences in platelet aggregation and bleeding time. No dosage adjustment is needed for the elderly.

Renal impairment.

After repeated doses of 75 mg clopidogrel per day, plasma levels of the main circulating metabolite were lower in patients with severe renal impairment (creatinine clearance from 5 to 15 mL/min) compared to subjects with moderate renal impairment (creatinine clearance 30 to 60 mL/min) or healthy subjects. Although inhibition of ADP-induced platelet aggregation was lower (25%) than that observed in healthy volunteers, the prolongation of bleeding time was similar in healthy volunteers receiving 75 mg of clopidogrel per day. No dosage adjustment is needed in renally impaired patients. However, experience with clopidogrel is limited in patients with severe renal impairment. Therefore clopidogrel should be used with caution in this population.

Gender.

In a small study comparing men and women, less inhibition of ADP-induced platelet aggregation was observed in women, but there was no difference in prolongation of bleeding time. In the large, controlled clinical study (Clopidogrel vs. Aspirin in Patients at Risk of Ischemic Events; CAPRIE), the incidence of clinical outcome events, other adverse clinical events, and abnormal clinical laboratory parameters was similar in men and women.

Ethnicity.

The prevalence of CYP2C19 alleles that result in intermediate and poor CYP2C19 metabolism differs according to race/ethnicity (see Section 5.2 Pharmacokinetic Properties, Pharmacogenetics). From literature, limited data in Asian populations are available to assess the clinical implication of genotyping of this CYP on clinical outcome events.

5.3 Preclinical Safety Data

Genotoxicity.

Clopidogrel was not genotoxic in four in vitro tests (Ames test, DNA-repair test in rat hepatocytes, gene mutation assay in Chinese hamster fibroblasts and metaphase chromosome analysis of human lymphocytes) and in one in vivo test (micronucleus test by the oral route in mice).

Carcinogenicity.

There was no evidence of carcinogenic effects when clopidogrel was given in the diet for 78 weeks to mice and 104 weeks to rats at doses up to 77 mg/kg per day (representing an exposure ~ 18 times the anticipated patient exposure, based on plasma AUC for the main circulating metabolite in elderly subjects).

6 Pharmaceutical Particulars

6.1 List of Excipients

Clopidogrel 75 mg film-coated tablets contain the following inactive ingredients: colloidal anhydrous silica, hypromellose, iron oxide red, mannitol, microcrystalline cellulose, stearic acid and titanium dioxide.

6.2 Incompatibilities

Incompatibilities were either not assessed or not identified as part of the registration of this medicine.

6.3 Shelf Life

In Australia, information on the shelf life can be found on the public summary of the Australian Register of Therapeutic Goods (ARTG). The expiry date can be found on the packaging.

6.4 Special Precautions for Storage

Store below 25°C. Protect from light.

6.5 Nature and Contents of Container

Clopidogrel APOTEX 75 mg film coated tablets are available in PVC/PVDC/Al blister packs of 28 tablets.

6.6 Special Precautions for Disposal

In Australia, any unused medicine or waste material should be disposed of by taking to your local pharmacy.

6.7 Physicochemical Properties

Chemical structure.

Chemical name: methyl (+)-(S)-alpha-(2-chlorophenyl)- 6,7- dihydrothieno[3,2-c] pyridine- 5(4H)-acetate besilate (1:1).
Molecular formula: C₁₆H₁₆ClNO₂S.C₆H₆O₃S.
Molecular weight: 479.99 (Free base: 321.82).

CAS number.

744256-69-7.
Clopidogrel besilate is a white to cream coloured crystalline powder. It is practically insoluble in water at neutral pH but freely soluble at pH 1. It is very soluble in methanol, ethanol, acetic acid and chloroform. It has a specific optical rotation of between +44° and +49°.

7 Medicine Schedule (Poisons Standard)

S4 (Prescription Only Medicine).

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