phentermine (Adipex-P)

Phentermine is a drug that suppresses appetite.

• Phentermine is combined with diet and exercise for the short-term treatment of obesity in individuals with a body mass index greater than or equal to 30 kg/m2 or greater than or equal to 27 kg/m2 with risk factors for heart disease.
• Phentermine should not be combined with other weight loss agents.
• The combination of phentermine and fenfluramine (FEN-PHEN) is associated with serious heart problems. Fenfluramine is no longer available in the United States.

Yes

Yes. It is a schedule IV controlled substance.

• Brand available in the US for phentermine are Adipex-P and Lomaira.
• Discontinued brands are Fastin, Oby-Trim, Obestin-30, OnaMast, Tora, Obenix, Suprenza, and Wilpo.

Side effects of phentermine include:

• nausea,
• vomiting,
• diarrhea,
• dry mouth,
• constipation,
• an unpleasant taste,
• hives,
• impotence,
• palpitations,
• high blood pressure, and
• fast heart rates (palpitations).

Central nervous system side effects include:

• hyperactivity,
• insomnia,
• restlessness,
• tremor, and
• dizziness.

Phentermine, especially when combined with fenfluramine, has been associated with high pressures in the pulmonary arteries (pulmonary hypertension) and defects in heart valves, both serious complications.

Physical and psychological dependence may occur with the long-term use of phentermine. A withdrawal reaction, which includes excessive drowsiness, fatigue, tremors and depression may occur after prolonged use.

• The recommended dose is 15-37.5 mg once daily.
• Adipex-P is administered about 1-2 hours after breakfast.
• The lowest effective dose should be used and evening doses should be avoided because phentermine causes insomnia.

• Phentermine is similar to amphetamine and may share some of the interactions associated with amphetamines. Combining phentermine with tricyclic antidepressants (for example, amitriptyline [Elavil, Endep]) or monoamine oxidase inhibitors or MAOIs (for example, phenelzine [Nardil], selegiline [Zelapar, Emsam, and Eldepryl], tranylcypromine [Parnate]) may result in high blood pressure and other serious reactions because of elevated serotonin levels in the blood. Phentermine should not be used within 14 days after stopping a monoamine oxidase inhibitor.
• People with diabetes being treated with phentermine may require a reduction in their dose of insulin or oral hypoglycemic drug.
• Combining alcohol with phentermine may result in an adverse drug reaction.

• Use of phentermine during pregnancy has not been adequately evaluated.
• It is not known whether phentermine is excreted in human breast milk. Since other amphetamines are excreted in breast milk, phentermine should not be used while breastfeeding or, if used, nursing should be discontinued.

What preparations of phentermine are available?

• Tablets: 8 and 37.5 mg.
• Capsules: 15, 30, 37.5 mg.

How should I keep phentermine stored?

Phentermine should be stored in a tight container at room temperature, 20 C to 25 C (68 F to 77 F).

How does phentermine work?

• The exact mechanism of action of phentermine is unknown. It probably decreases appetite by acting on centers in the brain that control appetite. Phentermine is similar to amphetamine. It stimulates the nervous system, elevates blood pressure, and increases heart rate.