phen·ter·mine / ˈfentərˌmēn/ • n. Med. a prescription appetite-suppressant drug that binds to receptors on the hypothalmus, and is one of the pair of drugs known as fen-phen. It is still prescribed independently for obesity, following the withdrawal of fenfluramine, the other component of fen-phen.

phentermine An appetite suppressant drug used in the treatment of obesity, especially in combination with fenfluramine (fen‐phen); withdrawn in 1995 because of reports of heart valve damage.