Phenmetrazine (INN, USAN, BAN) (brand name Preludin) is a stimulant drug containing a phenethylamine skeleton, in which the terminal amine is incorporated into a morpholine ring, that was previously used as an appetite suppressant, but has since been withdrawn from the market. It was initially replaced by its analogue phendimetrazine which functions as a prodrug to phenmetrazine, but now it is rarely prescribed, due to concerns of abuse and addiction.