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Journal of The Korean Society of Emergency Medicine 2010;21(3): 405-411. |
A Case of Electrocardiographic and Mental Change in a Patient with a Diphenhydramine Overdose |
Cheol Sang Park, In Gu Kang, Hyun Sik Ryu, Seong Soo Park, Mi Jin Lee, Won Joon Jeong |
Department of Emergency Medicine, Konyang University College of Medicine, Daejeon, Korea. gardenjun@naver.com |
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ABSTRACT |
The antihistaminic drug diphenhydramine is mainly used as a sedative, hypnotic and antiemetic. In many countries it is available over-the-counter, very common, and generally regarded as a harmless drug. However, diphenhydramine overdose can result in cardiotoxicity due to its ability to block fast sodium channels in a manner analogous to classic Vaughan-Williams type IA antidysrhythmic agents. As such, cardiotoxicity from diphenhydramine resembles that of the tricyclic antidepressant agents. Here we report a case of a 52 year old man who ingested 2,000 mg of diphenhydramine and presented with an altered mental state and an electrocardiographic change. His electrocardiogram showed sinus tachycardia with a rate 145 beat/min, a QRS interval of 88 ms, and a QTc of 556 ms. He had a wide anion gap metabolic acidosis. He was treated with intravenous sodium bicarbonate and supportive therapy. His clinical manifestations waned and he was transferred to another hospital nearby his hometown. |
Key words:
Diphenhydramine, Electrocardiography, Sodium bicarbonate, Acidosis, Overdose |
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