Consumer medicine information

What is in this leaflet

This leaflet answers some common questions about Amlodipine besylate.

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 Amlodipine besylate against the benefits it is expected to 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

The name of your medicine GTA-AMLODIPINE tablets. It contains the active ingredient amlodipine besylate.

What it does

This is used to:

• lower high blood pressure (hypertension).
  There are usually no symptoms of hypertension. The only way of knowing that you have hypertension is to have your blood pressure checked on a regular basis. If high blood pressure is not treated it can lead to serious health problems.
• treat angina pectoris.
  Angina is a pain or uncomfortable feeling in the chest, often spreading to the arms or neck, and sometimes to the shoulders and back. The pain of angina is due to a shortage of oxygen to the heart.
  This medicine is not for the relief of a sudden attack of angina. Your doctor will give you other medication to treat this.

How it works

This medicine belongs to a group of medicines called calcium channel blockers or calcium ion antagonists. They work by widening your blood vessels, making it easier for your heart to pump blood around the body and help increase the supply of blood and oxygen to your heart. Calcium channel blockers do not change the amount of calcium in your blood or bones.

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

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

Use in Children

There is not enough information to recommend the use of this medicine in children.

Before you take this medicine

When you must not take it

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

• this medicine, or any other medicine containing amlodipine
• other calcium channel blockers such as medicines with the active ingredient felodipine, nifedipine or lercanidipine.

Check with your doctor or pharmacist if you are unsure.

• 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 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:

• heart problems, including heart failure
• liver problems.

Tell your doctor if you are pregnant or plan to become pregnant. This medicine may affect your developing baby if you take it during pregnancy. Your doctor can discuss with you the risks and benefits involved.

Do not breast-feed if you are taking this medicine. It is not known if the active ingredient in this medicine passes into breast milk or if your baby may be affected.

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

Taking other medicines

Tell your doctor or pharmacist if you are taking any other medicines, including:

• all prescription medicines
• all medicines, vitamins, herbal supplements or natural therapies you buy without a prescription from a pharmacy, supermarket, naturopath or health food shop.

Some medicines may be affected by this medicine 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 will advise you.

Tell your doctor or pharmacist if you are taking any of the following:

• other medicines used to treat angina, such as diltiazem
• some antibiotics, such as erythromycin, clarithromycin or rifampicin
• some antifungals, such as ketoconazole or itraconazole
• anti-proteases, medicines used to treat HIV infection, such as ritonavir
• simvastatin, a medicine used to lower cholesterol
• cyclosporin or tacrolimus, medicines used to suppress the immune system
• St John's Wort.

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

How to take this medicine

Take this medicine exactly as your doctor has prescribed.

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 box, ask your doctor or pharmacist for help.

How much to take

The usual dose of this medicine is 5 mg each day. Your doctor may increase this to 10 mg each day.

Your doctor may prescribe another dose of this medicine depending on your condition and how you respond to this medicine.

How to take it

Swallow the tablet whole with a full glass of water.

When to take it

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

this medicine can be taken with or without food.

How long to take it

You must take this every day. 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 less than 12 hours before 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 Poisons Information Centre - the telephone number in Australia is 131 126 -for advice or go to Accident and Emergency at your nearest hospital if you think that you or anyone else may have taken too much this medicine.

Do this even if there are no signs of discomfort or poisoning. You may need urgent medical attention.

If you take too many tablets, you may feel dizzy, lightheaded or faint and have an irregular heartbeat.

While you are taking this medicine

Things you must do

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

If you are about to start any new medicine, tell your doctor or pharmacist that you are taking this medicine.

If you become pregnant while taking this medicine, tell your doctor immediately.

Keep all of 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.

Things you must not do

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

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

Things to be careful of

Avoid eating large quantities of grapefruit or drinking large quantities of grapefruit juice. Grapefruit juice contains one or more components that alter the metabolism of some medicines, including this medicine.

Drinking very large quantities (over 1.2 litres) of grapefruit juice each day while taking this medicine may increase the effects of this medicine.

Be careful driving or operating machinery until you know how this medicine affects you.

this medicine may cause dizziness or drowsiness in some people.

If you have any of these symptoms, do not drive, operate machinery or do anything else that could be dangerous.

Things that would be helpful for your high blood pressure or angina

Some self-help measures suggested below may assist your condition. Your doctor or pharmacist can give you more information about these measures.

• Weight: Your doctor may suggest losing some weight. Some people may need a dietician to plan a suitable diet to help with weight loss.
• Exercise: Regular exercise helps lower blood pressure and strengthen the heart. It is important not to overdo it. Before commencing regular exercise you should consult your doctor who will suggest the most suitable exercise for you. If you feel uncomfortable when exercising or experience symptoms such as chest pain or breathlessness see your doctor.
• Alcohol: Your doctor may advise you to limit your alcohol intake.
• Salt: Your doctor may advise you to watch the amount of salt in your diet. To reduce your salt intake you should avoid using salt at the table or in cooking.
• Smoking: Your doctor may advise you to stop smoking or at least cut down.

Side effects

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

this medicine helps most people but it may have some unwanted side effects in a few people. All medicines can have side effects. Sometimes they are serious, most of the time they are not. You may need medical attention if you get some of the side effects.

It can be difficult to tell whether side effects are the result of taking this medicine, effects of your condition or side effects of other medicines you may be taking. For this reason it is important to tell your doctor of any change in your condition.

Do not be alarmed by the list of possible side effects. You may not experience any of them.

Tell your doctor if...

Ask your doctor or pharmacist for advice if you experience any of the following and they worry you:

• headache
• dizziness
• flushing
• tiredness
• drowsiness or sleepiness
• stomach pain or nausea.

These are the more common side effects of this medicine. All side effects should be reported to a health professional.

Tell your doctor or pharmacist if you experience any of the following and they worry you:

• indigestion
• sexual problems.

These may or may not be due to this medicine but you should tell your doctor.

Tell your doctor as soon as possible if...

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

• changes in heart beat either fast or slow
• swelling of the ankles, feet, face or hands
• tingling or numbness of the hands or feet
• dizziness or lightheadedness on standing up from a sitting or lying position
• unusual tiredness or weakness
• muscle cramps or aches
• joint pain
• eye pain or change in vision
• changes in mood, feeling anxious or nervous
• symptoms of liver disease such as itching, yellowing of the skin and eyes, and dark coloured urine
• unusual movements, including trembling and shaking of the hands and fingers, twisting movements of the body, shuffling walk and stiffness of the arms and legs.

These may be serious side effects that may need urgent medical attention

Go to hospital if...

Tell your doctor immediately or go to Accident and Emergency at your nearest hospital, if you notice any of the following:

• fast or irregular heart beats
• chest pain
• chest pain associated with exertion (angina) that lasts longer, is more severe or occurs more often
• shortness of breath
• symptoms of allergy such as skin rash and/or itching
• severe upper stomach pain, often with nausea and vomiting.

The above list includes very serious side effects. You may need urgent medical attention or hospitalisation.

Ask your doctor or pharmacist to answer any questions you may have.

If you are 65 years or older, you should be especially careful while taking this medicine. Report any side effects promptly to your doctor. Some people in this age group may be more likely to experience side effects such as swelling of the feet and ankles, muscle cramps and dizziness.

Tell your doctor or pharmacist if you notice anything else that is making you feel unwell. Other side effects not listed above may also occur in some people.

After taking this medicine

Storage

Keep your tablets in the pack until it is time to take them. If you take your tablets out of the pack they may not keep as well.

Keep your tablets in a cool dry place where the temperature stays below 25°C.

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

Keep this medicine 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 tablets have passed their expiry date, ask your pharmacist what to do with any medicine that is left over.

Product description

What it looks like

This medicine tablets are available in two strengths:

• 5 mg tablets – white to off white, circular, biconvex, uncoated tablets debossed with ‘E21’ on one side and score line on the other side.
• 10 mg tablets - white to off white, round, uncoated tablets with ‘10’ debossing on one side.

The 5 mg and 10 mg tablets come in packs of 10's and 14’s. Further blisters are packed into an outer carton to give pack sizes of 10, 28, 30, 50, 56 and 84 tablets.

Ingredients

Active ingredients

• 5 mg tablets contain amlodipine besylate equivalent to amlodipine 5 mg.
• 10 mg tablets contain amlodipine besylate equivalent to amlodipine 10 mg.

Other ingredients

• microcrystalline cellulose
• calcium hydrogen phosphate
• sodium starch glycollate
• Silica-colloidal anhydrous
• magnesium stearate.

This medicine does not contain gluten, sugar or lactose.

Supplier

Ipca Pharma (Australia) Pty Ltd,
6 Morotai Avenue Ashburton VIC 3147, Australia

This leaflet was prepared in
February 2021

Australian Registration Number:
5 mg -264394 and 10 mg-264395

Published by MIMS October 2021

Name of the medicine

Amlodipine besilate.
Excipients. Microcrystalline cellulose, calcium hydrogen phosphate, sodium starch glycollate, silica-colloidal anhydrous, magnesium stearate. https://stagingapi.mims.com/au/public/v2/images/fullchemgif/CSAMLBES.gif

Description

Amlodipine tablets 5 mg and 10 mg.
Amlodipine tablets contains the active ingredient amlodipine besilate. Amlodipine besylate is a dihydropyridine derivative.
Chemical name: 3-ethyl-5-methyl-2-(2-aminoethoxymethyl)-4-(2-chlorophenyl)-1,4-dihydro-6-methyl-3,5-pyridinedicarboxylate benzene sulphonate.
Molecular formula: C₂₀H₂₅ClN₂O₅.C₆H₆O₃S. Molecular weight: 567.1 (free base 408.9).
CAS registry numbers: amlodipine 88150-42-9; amlodipine besylate 111470-99-6.
Amlodipine besylate is a white crystalline powder, and is slightly soluble in water and sparingly soluble in ethanol.
In addition to amlodipine besylate, each amlodipine tablets contains the following inactive ingredients: microcrystalline cellulose; calcium hydrogen phosphate; sodium starch glycollate; silica-colloidal anhydrous, magnesium stearate.

Pharmacology

Pharmacodynamics. Amlodipine is a calcium ion influx inhibitor (slow channel blocker or calcium ion antagonist) and inhibits the transmembrane influx of calcium ions into cardiac and vascular smooth muscle.
Experimental data suggest that amlodipine binds to both dihydropyridine and nondihydropyridine binding sites. The contractile processes of cardiac muscle and vascular smooth muscle are dependent upon the movement of extracellular calcium ions into these cells through specific ion channels. Amlodipine inhibits calcium ion influx across cell membranes selectively, with a greater effect on vascular smooth muscle cells than on cardiac muscle cells. Negative inotropic effects can be detected in vitro but such effects have not been seen in intact animals at therapeutic doses. Serum calcium concentration is not affected by amlodipine. Within the physiologic pH range, amlodipine is an ionised compound (pKa = 8.6), and its kinetic interaction with the calcium channel receptor is characterised by a gradual rate of association and dissociation with the receptor binding site, resulting in a gradual onset of effect.
Amlodipine is a peripheral arterial vasodilator that acts directly on vascular smooth muscle to cause a reduction in peripheral vascular resistance and reduction in blood pressure. The precise mechanism by which amlodipine relieves angina has not been fully determined, but amlodipine reduces the total ischaemic burden by the following two actions.
1. Amlodipine dilates peripheral arterioles and thus reduces the total peripheral resistance (afterload) against which the heart works. Since the heart rate remains stable, this unloading of the heart reduces myocardial energy consumption and oxygen requirements.
2. Amlodipine has been shown to block constriction in main coronary arteries and coronary arterioles, induced by calcium, potassium, adrenaline, serotonin and thromboxane A2 analogue both in normal and in ischaemic regions.
Haemodynamics. Following administration of therapeutic doses to patients with hypertension, amlodipine produces vasodilation resulting in a reduction of supine and standing blood pressures. These decreases in blood pressure are not accompanied by a significant change in heart rate or plasma catecholamine levels with chronic dosing. Although the acute intravenous administration of amlodipine decreased arterial blood pressure and increased heart rate in haemodynamic studies of patients with chronic stable angina, chronic administration of oral amlodipine in clinical trials did not lead to clinically significant changes in heart rate or blood pressures in normotensive patients with angina.
With chronic once-daily oral administration, antihypertensive effectiveness is maintained for at least 24 hours. Plasma concentrations correlate with effect in both young and elderly patients.
The magnitude of reduction in blood pressure with amlodipine is also correlated with the height of pretreatment elevation; thus, individuals with moderate hypertension (diastolic pressure 105 to 114 mmHg) had about a 50% greater response than patients with mild hypertension (diastolic pressure 90 to 104 mmHg). Normotensive subjects experienced no clinically significant change in blood pressures (+1/-2 mmHg).
As with other calcium channel blockers, haemodynamic measurements of cardiac function at rest and during exercise (or pacing) in patients with normal ventricular function treated with amlodipine have generally demonstrated a small increase in cardiac index without significant influence on dP/dt or on left ventricular end diastolic pressure or volume. In haemodynamic studies, amlodipine has not been associated with a negative inotropic effect when administered in the therapeutic dose range to intact animals and man, even when co-administered with beta-blockers to man. Similar findings, however, have been observed in normals or well-compensated patients with heart failure with agents possessing significant negative inotropic effects.
In hypertensive patients with normal renal function, therapeutic doses of amlodipine resulted in a decrease in renal vascular resistance and an increase in glomerular filtration rate and effective renal plasma flow without change in filtration fraction or proteinuria.
Pharmacokinetics. Absorption. After oral administration of therapeutic doses, amlodipine is well absorbed with peak blood levels between 6 and 12 hours post-dose. This may reflect significant initial uptake by the liver, followed by a phase of redistribution. This interval is shorter (2 to 8 hours) in patients with hepatic insufficiency. Absolute bioavailability has been estimated to be between 64% and 90%. The bioavailability of amlodipine is not altered by the presence of food. The volume of distribution is approximately 20 L/kg.
In vitro studies have shown that approximately 97.5% of circulating amlodipine is bound to plasma proteins.
Biotransformation/ elimination. The terminal plasma elimination half-life is about 35 to 50 hours and is consistent with once-daily dosing. Steady-state plasma levels are reached after 7 to 8 days of consecutive dosing.
Amlodipine is extensively metabolised by the liver to inactive metabolites, with 10% of the parent compound and 60% of metabolites excreted in the urine.
Special populations. Elderly (≥ 65 years). In elderly hypertensive patients (mean age 69 years) there was a decrease in clearance of amlodipine from plasma as compared to young volunteers (mean age 36 years) with a resulting increase in the area under the curve (AUC) of about 60%.

Clinical Trials

Studies in patients with congestive heart failure. Amlodipine has been compared to placebo in four 8 to 12 week studies of patients with New York Heart Association (NYHA) class II/III heart failure, involving a total of 697 patients. Although efficacy in regard to the primary and secondary endpoints was not demonstrated, there was no evidence of worsened heart failure based on measures of exercise tolerance, NYHA classification, symptoms, or LVEF. In a long-term (follow-up at least 6 months, mean 13.8 months) placebo-controlled mortality/morbidity study of amlodipine 5-10 mg in 1153 patients with NYHA classes III (n = 931) or IV (n = 222) heart failure on stable doses of diuretics, digoxin, and ACE inhibitors, amlodipine had no effect on the primary endpoint of the study which was the combined endpoint of all-cause mortality and cardiac morbidity (as defined by life-threatening arrhythmia, acute myocardial infarction, or hospitalisation for worsened heart failure), or on NYHA classification, or symptoms of heart failure. Total combined all-cause mortality and cardiac morbidity events were 222/571 (39%) for patients on amlodipine and 246/583 (42%) for patients on placebo: the cardiac morbid events represented about 25% of the endpoints in the study.
In this study, amlodipine was associated with increased reports of pulmonary oedema despite no significant difference in the incidence of worsening heart failure compared to placebo.
Electrophysiologic effects. Amlodipine does not change sinoatrial nodal function or atrioventricular conduction in intact animals or man. In patients with chronic stable angina, intravenous administration of 10 mg of amlodipine and a further 10 mg of amlodipine after a 30 minute interval produced peripheral vasodilation and afterload reduction, but did not significantly alter A-H and H-V conduction and sinus node recovery time after pacing. Similar results were obtained in patients receiving amlodipine and concomitant beta-blockers. In clinical studies in which amlodipine was administered in combination with beta-blockers to patients with either hypertension or angina, no adverse events on electrocardiographic parameters were observed. In clinical trials with angina patients alone, amlodipine therapy did not alter electrocardiographic intervals or produce higher degrees of AV blocks.
Effects in hypertension. In patients with hypertension once-daily dosing provides clinically significant reductions in blood pressure in both the supine and standing positions throughout the 24 hour interval post dose. Due to the slow onset of action, acute hypotension is not a feature of amlodipine administration. The blood pressure effect is maintained over the 24 hour dosing interval, with little difference in peak and trough effect. Tolerance has not been demonstrated in patients studied for up to 1 year. Effects on diastolic pressure were similar in young and older patients. The effect on systolic pressure was greater in older patients, perhaps because of greater baseline systolic pressure.
Effects in chronic stable angina. In patients with angina, once-daily administration of amlodipine increases total exercise time to angina onset and total work time to 1 mm ST segment depression and decreases both angina attack frequency and nitroglycerine tablet consumption. The sustained efficacy of amlodipine in angina patients has been demonstrated over long-term dosing. In patients with angina there were no clinically significant reductions in blood pressures (4/1 mmHg) or changes in heart rate (+0.3 bpm).
Other. In clinical trials amlodipine has shown no harmful effect on lipid levels. Dihydropyridine calcium channel blockers have not been associated with any adverse metabolic effects and are suitable for use in patients with asthma, diabetes and gout.

Indications

1. Hypertension. Amlodipine is indicated for the first line treatment of hypertension and can be used as the sole agent to control blood pressure in the majority of patients. Patients not adequately controlled on a single antihypertensive agent may benefit from the addition of amlodipine, which has been used in combination with a thiazide diuretic, beta adrenoceptor blocking agent or an angiotensin-converting enzyme inhibitor.
2. Angina. Amlodipine is indicated for the first line treatment of chronic stable angina. Amlodipine may be used alone, as monotherapy or in combination with other antianginal drugs.

Contraindications

Amlodipine is contraindicated in patients with a known hypersensitivity to amlodipine, other dihydropyridines, or any of the inactive ingredients.

Precautions

Increased angina. Rarely patients, particularly those with severe obstructive coronary artery disease, have developed documented increased frequency, duration and/or severity of angina on starting calcium channel blocker therapy or at the time of dosage increase. The mechanism of this effect has not been elucidated.
Outflow obstruction (aortic stenosis). Amlodipine should be used with caution in the presence of a fixed left ventricular outflow obstruction (aortic stenosis).
Use in patients with congestive heart failure. In general, calcium channel blockers should be used with caution in patients with heart failure. Amlodipine (5 mg to 10 mg per day) has been studied in a placebo-controlled trial of 1153 patients with NYHA class III or IV heart failure on stable doses of ACE inhibitor, digoxin and diuretics. Follow-up was at least 6 months, with a mean of about 14 months. There was no overall adverse effect on survival or cardiac morbidity (as defined by life-threatening arrhythmia, acute myocardial infarction, or hospitalisation for worsened heart failure). Amlodipine has been compared to placebo in four 8 to 12 week studies of patients with NYHA class II/III heart failure, involving a total of 697 patients. In these studies, there was no evidence of worsened heart failure based on measures of exercise tolerance, NYHA classification, symptoms, or LVEF.
Beta-blocker withdrawal. Amlodipine is not a beta-blocker and therefore provides no protection against the dangers of abrupt beta-blocker withdrawal; any such withdrawal should be by gradual reduction of the dose of beta-blocker.
Use in hepatic impairment. There are no adequate studies in patients with liver dysfunction and dosage recommendations have not been established. In a small number of patients with mild to moderate hepatic impairment given single doses of 5 mg, amlodipine half-life has been prolonged. Worsening of liver function test values may occur. Amlodipine should, therefore, be administered with caution in these patients and careful monitoring should be performed. A lower starting dose may be required (see Dosage and Administration).
Use in renal impairment. Amlodipine is extensively metabolised to inactive metabolites with 10% excreted as unchanged drug in the urine. Changes in amlodipine plasma concentrations are not correlated with the degree of renal impairment. Amlodipine may be used at normal doses in patients with renal failure. Amlodipine is not dialysable.
Peripheral oedema. Mild to moderate peripheral oedema was the most common adverse event in the clinical trials (see Adverse Effects). The incidence of peripheral oedema was dose-dependent and ranged in frequency from 3.0 to 10.8% in the 5 mg to 10 mg dose range. Care should be taken to differentiate this peripheral oedema from the effects of increasing left ventricular dysfunction.
Use in pregnancy. (Category C)
Calcium channel blockers carry the potential to produce fetal hypoxia associated with maternal hypotension. Accordingly they should not be used in pregnant women unless the potential benefit outweighs the risk to the fetus.
The safety of amlodipine in human pregnancy or lactation has not been established. In animal studies, amlodipine did not affect fertility in rats at oral doses up to 18 mg/kg (base) and had no teratogenic effects in rats (18 mg/kg) or rabbits (10 mg/kg). Amlodipine (10 mg/kg as besylate salt, 7 mg/kg base), administered orally to rats at or near parturition induced a prolongation of gestation time, an increase in the number of stillbirths and a decreased postnatal survival.
Use in lactation. It is not known whether amlodipine is excreted in human milk. In the absence of this information, breast-feeding should be discontinued during treatment with amlodipine.
Paediatric use. Safety and effectiveness have not been established in children.
Use in the elderly. In elderly patients (≥ 65 years) clearance of amlodipine is decreased with a resulting increase in AUC. In clinical trials the incidence of adverse events in elderly patients was approximately 6% higher than that of younger population (< 65 years). Adverse events include oedema, muscle cramps and dizziness. Amlodipine should be used cautiously in elderly patients.
Carcinogenicity. The carcinogenic potential of amlodipine has not been fully elucidated. Amlodipine did not induce any tumours when tested in rats at oral doses up to 2.5 mg/kg. This dose gave rise to plasma levels that are similar to those achieved clinically.

Interactions

Amlodipine has been safely administered with thiazide diuretics, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, long-acting nitrates, sublingual nitroglycerine, non-steroidal anti-inflammatory drugs, antibiotics and oral hypoglycaemic drugs.
Special studies have indicated that the co-administration of amlodipine with digoxin did not change serum digoxin levels or digoxin renal clearance in healthy volunteers, and that co-administration of cimetidine did not alter the pharmacokinetics of amlodipine; and that co-administration with warfarin did not change the warfarin prothrombin response time.
In vitro data from studies with human plasma indicate that amlodipine has no effect on protein binding of the drugs tested (digoxin, phenytoin, warfarin or indomethacin).
Simvastatin. Co-administration of multiple doses of amlodipine and simvastatin resulted in an increase in exposure to simvastatin compared to simvastatin alone. The product information for simvastatin should be reviewed for the appropriate dose of simvastatin when the patient is prescribed amlodipine concurrently.
Grapefruit juice. Grapefruit juice is known to inhibit the cytochrome P450 system, thereby affecting the pharmacokinetics of drugs such as calcium channel blockers. Administration of amlodipine with grapefruit or grapefruit juice is not recommended as bioavailability may be increased in some patients, resulting in increased blood pressure lowering effects.
CYP3A4 inhibitors. With concomitant use with the CYP3A4 inhibitor erythromycin in young patients and diltiazem in elderly patients, the plasma concentration of amlodipine was increased. The clinical relevance of this finding is uncertain. It cannot be ruled out that strong inhibitors of CYP3A4 (e.g. ketoconazole, itraconazole, ritonavir) may increase the plasma concentrations of amlodipine to a greater extent than diltiazem. Amlodipine should be used with caution when administered with CYP3A4 inhibitors.
Clarithromycin. Clarithromycin is an inhibitor of CYP3A4. There is an increased risk of hypotension in patients receiving clarithromycin with amlodipine. Close observation of patients is recommended when amlodipine is co-administered with clarithromycin.
CYP3A4 inducers. There are no data available regarding the effect of CYP3A4 inducers on amlodipine. Concomitant use of CYP3A4 inducers (e.g. rifampicin, Hypericum perforatum (St. John's Wort)) may decrease the plasma concentrations of amlodipine. Amlodipine should be used with caution when administered with CYP3A4 inducers.
Aluminium/ magnesium (antacid). Co-administration of an aluminium/magnesium antacid with a single dose of amlodipine had no significant effect on the pharmacokinetics of amlodipine.
Sildenafil. A single 100 mg dose of sildenafil in 16 patients with essential hypertension had no effect on the pharmacokinetic parameters of amlodipine. When amlodipine and sildenafil were used in combination, each agent independently exerted its own blood pressure lowering effect.
Atorvastatin. Co-administration of multiple 10 mg doses of amlodipine with 80 mg atorvastatin resulted in no significant change in the steady-state pharmacokinetic parameters of atorvastatin.
Ethanol (alcohol). Single and multiple 10 mg doses of amlodipine had no significant effect on the pharmacokinetics of ethanol.
Cyclosporin. No drug interaction studies have been conducted with cyclosporin and amlodipine in healthy volunteers or other populations, with the exception of renal transplant patients. Various studies in renal transplant patients report that co-administration of amlodipine with cyclosporin affects the trough concentrations of cyclosporin, and consideration should be given for monitoring cyclosporin levels in renal transplant patients on amlodipine.
Tacrolimus. There is a risk of increased tacrolimus blood levels when co-administered with amlodipine. In order to avoid toxicity of tacrolimus, administration of amlodipine in a patient treated with tacrolimus requires monitoring of tacrolimus blood levels and dose adjustment of tacrolimus when appropriate.

Adverse effects

Amlodipine has been evaluated for safety in more than 11,000 patients in clinical trials worldwide.
In general, treatment with amlodipine was well-tolerated at doses up to 10 mg daily. Most adverse events reported during therapy with amlodipine were of mild or moderate severity. In controlled clinical trials directly comparing amlodipine (N = 1,730) in doses up to 10 mg to placebo (N = 1,250), discontinuation of amlodipine due to adverse events was required in only about 1.5% of patients and was not significantly different from placebo (about 1%). Amlodipine therapy has not been associated with clinically significant changes in routine laboratory tests. No clinically relevant changes were noted in serum potassium, serum glucose, total triglycerides, total cholesterol, HDL cholesterol, uric acid, blood urea nitrogen or creatinine or liver function tests.
The most common side effects are headache and oedema. The incidence (%) of side effects which occurred in a dose-related manner is shown in Table 1.
https://stagingapi.mims.com/au/public/v2/images/fulltablegif/GTAAML01.gif Other adverse experiences which were not clearly dose-related but which were reported with an incidence greater than 1.0% in placebo-controlled clinical trials is shown in Table 2.
https://stagingapi.mims.com/au/public/v2/images/fulltablegif/GTAAML02.gif The following events occurred in ≤ 1% but > 0.1% of patients in controlled clinical trials or under conditions of open trials or marketing experience where a causal relationship is uncertain; they are listed to alert the physician to a possible relationship.
Blood and lymphatic system disorders. Leucopenia, thrombocytopenia.
Cardiac disorders. Tachycardia.
Ear and labyrinth disorders. Tinnitus, vertigo.
Eye disorders. Abnormal vision, conjunctivitis, diplopia, eye pain.
Gastrointestinal disorders. Altered bowel habits, constipation, diarrhoea, dry mouth, dyspepsia*, dysphagia, flatulence, gingival hyperplasia, pancreatitis, vomiting.
General disorders and administration site conditions. Asthenia*, malaise, pain, rigors, thirst.
Immune system disorders. Allergic reactions.
Investigations. Weight gain.
Metabolism and nutrition disorders. Anorexia, hyperglycaemia.
Musculoskeletal and connective tissue disorders. Arthralgia, arthrosis, back pain, muscle cramps*, myalgia.
Nervous system disorders. Hypoesthesia, paresthesia, peripheral neuropathy, postural dizziness, syncope, tremor.
Psychiatric disorders. Abnormal dreams, anxiety, depersonalisation, depression, insomnia, mood changes, nervousness.
Renal and urinary disorders. Micturition disorder, micturition frequency, nocturia.
Reproductive system and breast disorders. Gynaecomastia, sexual dysfunction (male* and female).
Respiratory, thoracic and mediastinal disorders. Dyspnoea*, epistaxis.
Skin and subcutaneous tissue disorders. Alopecia, angioedema, pruritus*, purpura, rash*, rash erythematous, rash maculopapular, sweating increased.
Vascular disorders. Hot flushes, hypotension, peripheral ischaemia, postural hypotension, vasculitis.
* These events occurred in less than 1% of patients in placebo-controlled trials, but the incidence of these adverse effects was between 1% and 2% in all multiple dose studies.
The following events occurred in ≤ 0.1% of patients: cardiac failure, pulse irregularity, extrasystoles, skin discolouration, urticaria, skin dryness, dermatitis, erythema multiforme, muscle weakness, twitching, ataxia, hypertonia, migraine, cold and clammy skin, apathy, agitation, amnesia, gastritis, increased appetite, loose stools, coughing, rhinitis, dysuria, polyuria, parosmia, taste perversion, abnormal visual accommodation, xerophthalmia and weight decrease.
As with other calcium channel blockers the following adverse events have been rarely reported and cannot be distinguished from the natural history of the underlying disease: myocardial infarction, arrhythmia (including bradycardia, ventricular tachycardia and atrial fibrillation) and chest pain.
There have been infrequent, post-marketing reports of hepatitis, jaundice and hepatic enzyme elevations (mostly consistent with cholestasis). Some cases severe enough to require hospitalisation have been reported in association with use of amlodipine. In many instances, causal association is uncertain.
There have been post-marketing reports of extrapyramidal disorder in association with use of amlodipine.
Amlodipine has been used safely in patients with chronic obstructive pulmonary disease, well compensated congestive heart failure, peripheral vascular disease, diabetes mellitus and abnormal lipid profiles.

Dosage and Administration

For hypertension or angina, the usual initial dose is 2.5 mg to 5 mg once-daily which may be increased to a maximum dose of 10 mg depending on the individual patient's response.
Small, fragile or elderly individuals, or patients with hepatic insufficiency should be started on 2.5 mg once-daily and this dose may be used when adding amlodipine to other antihypertensive therapy.
Dosage should be adjusted according to each patient's need. In general, titration should proceed over 7 to 14 days so that the physician can fully assess the patient's response to each dose level. Titration may proceed more rapidly, however, if clinically warranted, provided the patient is assessed frequently. See Adverse Effects for information related to dosage and adverse effects.
Co-administration with other antihypertensive and/or antianginal drugs. Amlodipine has been safely administered with thiazides, ACE inhibitors, beta-blockers, long-acting nitrates, and/or sublingual nitroglycerin.
No dose adjustment of amlodipine is required upon concomitant administration of thiazide diuretics, beta-blockers, long-acting nitrates and ACE inhibitors.

Overdosage

Available data suggest that overdose might be expected to cause excessive peripheral vasodilation with marked hypotension and possibly a reflex tachycardia. Dysrhythmias may occur following overdose with any calcium antagonist. Hypotension and bradycardia are usually seen within 1 to 5 hours following overdose. Hypotension can persist for longer than 24 hours despite treatment. Cardiac rhythm disturbances have been noted to persist for up to 7 days. Marked and probably prolonged systemic hypotension, up to and including shock with fatal outcome, have been reported.
Reports of intentional overdose include a patient who ingested 250 mg and was asymptomatic and was not hospitalised; another (120 mg) was hospitalised, underwent gastric lavage and remained normotensive; a third one (105 mg) was hospitalised and had hypotension (90/50 mmHg) which normalised following plasma expansion. Death resulted from a mixed overdose of 140 mg and 10 mefenamic acid capsules in a 15-year old girl, and from a mixed overdose of amlodipine 70 mg and an unknown quantity of oxazepam in a 63-year old woman. A case of accidental drug overdose has been documented in a 19 month old male who ingested 30 mg amlodipine (about 2 mg/kg). During the emergency room presentation, vital signs were stable with no evidence of hypotension, but a heart rate of 180 bpm.
If massive overdose should occur, active cardiac and respiratory monitoring should be instituted. Frequent blood pressure measurements are essential. Should hypotension occur, cardiovascular support, including elevation of the extremities, and the judicious administration of fluids should be initiated. If hypotension remains unresponsive to these conservative measures, administration of vasopressors (such as phenylephrine), should be considered with attention to circulating volume and urine output. Intravenous calcium may help to reverse the effects of calcium entry blockade. Administration of activated charcoal to healthy volunteers immediately or up to 2 hours after ingestion of amlodipine 10 mg has been shown to significantly decrease amlodipine absorption. In patients who are not fully conscious or have impaired gag reflex, consideration should be given to administering activated charcoal via nasogastric tube once the airway is protected. Ipecac-emesis is not recommended since haemodynamic instability and CNS depression may rapidly develop. Since amlodipine is highly protein-bound, dialysis is not likely to be of benefit.
Contact the Poisons Information Centre on 13 11 26 for advice on the management of an overdose.

Presentation

GTA-Amlodipine 5 mg is available as white to off white, circular, biconvex, uncoated tablets debossed with 'E21' embossing on one side and score line on other side. It contains amlodipine besylate equivalent to 5 mg of amlodipine.
GTA-Amlodipine 10 mg is available as white to off white, round, biconvex, uncoated tablets with '10' debossing on one side. It contains amlodipine besylate equivalent to 10 mg of amlodipine.
5 mg and 10 mg are packaged in opaque PVDC coated PVC/ aluminium blister pack of 10 or 14 tablets. Further blisters are packed into an outer carton to give pack sizes of 10, 28, 30, 50, 56 and 84 tablets (AUST R 264394 and 264395)*.

Storage

Store below 25°C.

Poison schedule

Prescription Only Medicine (S4).