Phentermine: Price, Dosage & Where to Buy

Phentermine is a sympathomimetic amine anorectic used as a short-term adjunct to weight reduction. It is generally prescribed alongside exercise, behavioural modification and caloric restriction for exogenous obesity in adults meeting the label's body mass index criteria. Phentermine is available as a generic medicine and requires a prescription in the United Kingdom.

Phentermine is indicated as a short-term adjunct in a weight-reduction programme based on exercise, behavioural modification and caloric restriction. It is used for the management of exogenous obesity, where excess weight is not caused by another medical condition. The label describes use for patients with an initial body mass index of at least 30 kg/m2, or at least 27 kg/m2 when other risk factors are present, such as controlled hypertension, diabetes or hyperlipidaemia.

The medicine is intended to support a broader weight-management plan rather than replace changes to eating habits or physical activity. Its use is short term, described in the label as a few weeks.

The label lists oral capsules in 15 mg, 30 mg, and 37.5 mg strengths, and oral tablets in 8 mg, 30 mg, and 37.5 mg strengths. The usual starting dose is one 37.5 mg capsule daily as prescribed by a physician, or one 37.5 mg tablet daily as prescribed by a physician. The label lists administration before breakfast or 1 to 2 hours after breakfast for appetite control.

The label lists that a half tablet of 18.75 mg daily may be adequate for some patients, while half tablets of 18.75 mg two times a day may be suitable in some cases. The label lists a maximum dosage of 15 mg daily for severe renal impairment with eGFR 15 to 29 mL/min/1.73m2.

Late evening administration should be avoided because of the risk of insomnia. The label lists that use should be avoided when eGFR is less than 15 mL/min/m2 or in end-stage renal disease requiring dialysis.

Phentermine is a sympathomimetic amine anorectic. Medicines in this class stimulate parts of the nervous system associated with alertness and appetite control. This can reduce feelings of hunger and support reduced calorie intake while a person follows a weight-reduction programme.

The medicine is chemically and pharmacologically related to amphetamine and other stimulant medicines, so it can also produce effects such as restlessness, insomnia, tremor, palpitations or an increase in blood pressure. The appetite-suppressing effect can lessen as tolerance develops. Phentermine does not replace exercise, behavioural modification or caloric restriction, which remain part of the treatment programme described in the label.

Phentermine is contraindicated during pregnancy because weight loss offers no potential benefit to a pregnant woman and may result in fetal harm. Animal reproduction studies have not been conducted with phentermine. Phentermine is also contraindicated during nursing.

It is not known if phentermine is excreted in human milk, although other amphetamines are present in human milk. A decision should be made whether to discontinue nursing or discontinue the medicine, considering its importance to the mother.

A missed dose should be handled according to the prescriber or pharmacist's advice. The label describes phentermine as a short-term medicine and warns against exceeding the recommended dose when appetite-suppressing effects lessen. A missed dose should not be replaced by taking extra medicine.

Late evening administration should be avoided because of the possibility of insomnia. Advice should be sought if several doses are missed or if there is uncertainty about the next scheduled dose.

Store at 20° to 25°C (68° to 77°F), in a tight container with a child-resistant closure. Keep phentermine and all medicines out of the reach of children. Protect the medicine from unsuitable storage conditions and keep it in its original container to maintain quality.