Antihistamine Toxicity

In 1943, as the planet was engulfed in WWII and the United States was officially announcing the end of The Great Depression, the most common modern antihistamine, diphenhydramine, was first synthesized. Shortly after, in 1947, orphenadrine was synthesized and used for the treatment of Parkinson disease. As the 1950s started, antihistamine use became more prevalent, and pediatric deaths increased. A comparison to atropine poisoning and their similar pharmacologic properties were soon realized. The specific concern of antihistamine toxicity is not a result of their competitive H1-receptor binding and sedation but due to their anticholinergic effect. Toxic exposure causes varying degrees of symptoms with differing implications. Treatment for antihistamine exposure can range from close monitoring and supportive therapy to rapid pharmacologic intervention.