Intensive hospital monitoring study of intravenous cimetidine.

We studied the frequency of adverse reactions occurring in 1189 patients who received cimetidine intravenously, based on data collected as part of a hospital-based monitoring study of recently marketed drugs. There were 40 patients (3.4%) with adverse reactions, 23 of whom were considered to be "definitely" or "probably" related to cimetidine use and 17 patients in whom a causal association was possible. The most frequently reported reactions were neuropsychiatric disorders in 19 patients (1.6%) and leukopenia in eight patients (0.7%).