THE TOXICITY OF BENADRYL: REPORT OF A CASE AND REVIEW OF THE LITERATURE

Abstract

A case of urticaria, edema and arthralgia probably due to penicillin sensitivity is reported. This patient did not respond to 150 mg. /day of benadryl but became completely well with a daily dose of 600 mg. On this high dosage the patient developed many untoward reactions including hallucinations and jerky, rapid speech which are reported for the first time. A review of the literature revealed that toxic reactions from the therapeutic use of benadryl are common, occurring in 46.4% of patients. With intraven. therapy, toxic reactions are more frequent, occurring in 65% of patients, are more acute, somewhat more severe and of shorter duration. The 5 most common reactions are, in order of frequency, drowsiness, dizziness, dry oral cavity, nausea and nervousness. A classification of toxic reactions is presented. Some reactions have occurred only with the intraven. use of the drug. The relation of symptoms to dosage is discussed. Mention is made of the hazards that may result from toxic reactions and measures for avoiding or minimizing untoward reactions are noted. The drug was discontinued because of toxic reactions in 6.4% of 1929 patients. Toxic reactions are relieved shortly after discontinuing the drug. There is no evidence of cumulative toxic effect. Because of these 2 facts it is concluded that the toxicity of benadryl, despite the frequency of side reactions, is low.