n. an appetite suppressant with a mechanism of action similar to the amphetamines. Like other appetite suppressants, it is effective only for short-term weight loss; long-term results require concurrent adherence to effective behavioral weight-loss strategies. Phentermine was previously marketed in combination with fenfluramine or dexfenfluramine—a combination known as “phen-fen”—which was taken off the market after cases of pulmonary hypertension and heart-valve disease were reported in users. These serious side effects may also occur with the use of phentermine alone. It should not be given in combination with monoamine oxidase inhibitors and should be used with caution in individuals taking SSRI antidepressants. U.S. trade names: Adipex; Ionamin.