Phentermine, also known as alpha, alpha-dimethylphenethylamine (contracted from phenyl-tertiary-butylamine), is a psychostimulant drug in the chemical class substituted for amphetamine, with an amphetamine-like pharmacology. It is used medically as a short-term appetite suppressant, as an adjunct to exercise and to minimize calorie intake.
Cardiovascular, gastrointestinal, and CNS side effects may occur with Phentermine; rare cases of pulmonary hypertension and cardiac valve disease have been recorded. People who have a history of substance abuse, have cardiovascular disease, hyperthyroidism, glaucoma, or are pregnant, expect to become pregnant, or are breast-feeding do not use it. Anybody taking a monoamine oxidase inhibitor does not take it. Drinking alcohol can cause adverse effects when using phentermine.
It was first introduced in 1959 and became part of the fen-phen drug mixture that was withdrawn from the market in 1997 due to the portion of fenfluramine damaging the heart valves of people. A separate combination drug, phentermine/topiramate, was approved in the US in 2012.
In several countries, under different brand names, different formulations of phentermine as a single agent are available.