cimetidine

noun1

1. •
   A histamine H₂-receptor antagonist that inhibits the production of acid in the stomach, mainly used to treat heartburn and peptic ulcers, but notorious for causing male impotence. It is a histamine analog, a sulfur-containing derivative of imidazole.

   • Until Tagamet (cimetidine), most major drug companies didn't take tummy troubles terribly seriously. — 1985