Consumer medicine information

1. Why am I using Phentodur?

Phentodur contains the active ingredient phentermine. Phentodur is used to reduce body weight in obese or overweight patients. For more information, see Section 1. Why am I using Phentodur? in the full CMI.

2. What should I know before I use Phentodur?

Do not use if you have ever had an allergic reaction to phentermine or any of the ingredients listed at the end of the CMI.
There are a number of circumstances in which a person should not use this medicine or may need to use caution. It is important to understand if these apply to you before taking Phentodur (see the full CMI for more details).
Talk to your doctor if you have any other medical conditions, take any other medicines, or are pregnant or plan to become pregnant or are breastfeeding.
For more information, see Section 2. What should I know before I use Phentodur? in the full CMI.

3. What if I am taking other medicines?

Some medicines may interfere with Phentodur and affect how it works.
A list of these medicines is in Section 3. What if I am taking other medicines? in the full CMI.

4. How do I use Phentodur?

• Carefully follow all directions given by your doctor or other healthcare professionals and never change the dose yourself.

• The usual dose of Phentodur is one capsule a day.

• Swallow the capsule whole with plenty of water. Do not chew or open the capsules.

5. What should I know while using Phentodur?

6. Are there any side effects?

Common side effects include changes in your heartbeat, high blood pressure, restlessness, trouble sleeping, nervousness, tremor, headache, dizziness, fainting, nausea, vomiting, diarrhoea or constipation, stomach cramps, dry or unpleasant taste in mouth, trouble urinating, skin rashes, sexual function problems, feelings of extreme happiness followed by depression and tiredness.
Serious side effects include heart attack, stroke, chest pain, myocardial infarction and difficulty breathing.
For more information, including what to do if you have any side effects, see Section 6. Are there any side effects? in the full CMI.

1 Name of Medicine

Phentermine (as hydrochloride).

2 Qualitative and Quantitative Composition

Each Phentodur capsule contains phentermine as an ion-exchange resin complex equivalent to 15, 30 or 40 mg phentermine depending on strength.
Excipients of known effect. Lactose monohydrate and sulphites (from gelatin capsules).
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Modified release capsules.
15 mg. Grey and green coloured, marked with 'PHE15'.
30 mg. Grey and reddish brown, marked with 'PHE30'.
40 mg. Grey and orange, marked with 'PHE40'.
The ion-exchange resin is quite stable, highly insoluble and without pharmacological effect until it reacts with cations (hydrogen, potassium, sodium etc.) present in the gastrointestinal fluids. Phentermine is then released from the resin complex at a rate dependent on the total concentration of these cations. Since this concentration is fairly constant throughout the entire gastrointestinal tract, continuous and controlled ionic release occurs over a 10 to 14 hour period.

4 Clinical Particulars

4.9 Overdose

Symptoms. Initially irritability, rapid respiration, agitation, euphoria, restlessness, hyperreflexia, disorientation and tremor, aggressiveness, hallucinations and panic states may occur, followed by cardiac arrhythmias, convulsions, fatigue, central nervous system depression and coma. Cardiovascular consequences include hypertension, hypotension and circulatory collapse. Gastrointestinal symptoms include nausea, vomiting, diarrhoea and abdominal cramps.
Treatment. The treatment is largely symptomatic. Activated charcoal may reduce absorption of the medicine if given within one or two hours after ingestion. In patients who are not fully conscious or have impaired gag reflex, consideration should be given to administering activated charcoal via a nasogastric tube, once the airway is protected. Diazepam, preferably by mouth (cautiously by intravenous injection) can be used to control marked excitement and convulsions. Provided renal function is adequate, elimination of phentermine has been shown to be assisted by acidification of the urine. There is insufficient experience to recommend haemodialysis or peritoneal dialysis.
For information on the management of overdose, contact the Poisons Information Centre on 13 11 26 (Australia).

5 Pharmacological Properties

5.3 Preclinical Safety Data

Genotoxicity. Phentermine was not mutagenic in a bacterial gene mutation assay, however, studies to assess the potential for chromosomal damage have not been performed.
Carcinogenicity. No studies have been performed to determine the potential of phentermine for carcinogenesis.

6 Pharmaceutical Particulars

6.7 Physicochemical Properties

Chemical structure. Phentermine (phenyl tertiary butylamine, C₁₀H₁₅N). The chemical structure is:
https://stagingapi.mims.com/au/public/v2/images/fullchemgif/CSPHENTE.gif CAS number. CAS No: Phentermine 122-09-8 (Phentermine hydrochloride 1197-21-3).

7 Medicine Schedule (Poisons Standard)

S4 - Prescription Only Medicine.

Summary Table of Changes

https://stagingapi.mims.com/au/public/v2/images/fulltablegif/PHENTOST.gif