Diphenhydramine and Acute Dystonia

Excerpt

To the Editor: Metoclopramide in high doses is widely used to prevent nausea and vomiting induced by cancer chemotherapy (1). Extrapyramidal reactions are a well-known side effect of metoclopramide therapy, and diphenhydramine, an ethanolamine and H₁-blocker, has been used in an attempt to prevent these reactions (2). A previously undescribed side effect of intravenous diphenhydramine is an acute dystonic reaction similar to that caused by metoclopramide. This type of reaction is supposed to be prevented by diphenhydramine administration.

A 66-year-old woman, who had not had psychiatric or central nervous system disturbances but had non-small-cell lung cancer, received diphenhydramine (Benadryl, Parke