Diphenhydramine is a first-generation antihistamine with anticholinergic and sedative properties. It is most commonly used for the treatment of nausea, vomiting, allergic rhinitis, mild to severe allergic reactions (e.g., anaphylaxis), and as a mild sleep aid. While used for a wide array of medical indications, diphenhydramine is also one of the most commonly abused medications in the United States (U.S.). Acute intoxications of diphenhydramine can have severe, potentially fatal consequences if not managed appropriately in a timely manner.
Huynh DA, Abbas M, Dabaja A. Diphenhydramine toxicity. 2022 May 8. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan–. PMID: 32491510.