/ Thesaurus / P Synonyms of periactin Find synonyms for: Noun1. cyproheptadine, Periactin, antihistamineusage: an antihistamine (trade name Periactin) used to treat some allergic reactionsWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: feline Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language