A pharmacologic investigation of dimethpyrindene maleate (forhistal ®)

Dimethpyrindene is intrinsically a potent, long lasting, orally effective antihistaminic, antiallergic drug. The specific antihistaminic activity of dimethpyrindene and its low oral toxicity have resulted in the highest therapeutic ratio reported for an antihistaminic drug. Dimethpyrindene does not possess marked anticholinergic activity nor did it potentiate the pressor action of l-epinephrine or l-norepinephrine. Dimethpyrindene was found to have a mild natriuretic and diuretic action when administered orally to unanesthetized dogs. Dimethpyrindene was found to inhibit the in vivo effects of histamine on the intestine of the anesthetized dog. In addition to its increased potency, dimethpyrindene has a significantly longer duration of action, both in vitro and in vivo, than the other antihistaminic drugs employed in this study.