Thioperamide is an antihistamine at H3 and H4 receptors. Thioperamide behaves as both antagonist and inverse agonist.Thioperamide is under preclinical development with Glaxo Wellcome (UK) for the treatment of short-term memory impairment. It has also demonstrated antiarrhythmic effects in preclinical trials. Active development of thioperamide appears to have been discontinued.