Evaluation of a non-Food and Drug Administration-approved use of cimetidine: treatment of pruritus resulting from epidural morphine analgesia

The purpose of this study was to evaluate the efficacy of a frequently used treatment at our hospital, intravenous cimetidine hydrochloride for pruritus resulting from epidural morphine sulfate analgesia in cesarean-section patients. Fifty-two patients were randomly assigned to receive either placebo or cimetidine 300 mg i.v. Thirty-nine patients experienced itching. Thirty-three patients completed the study (17 in the cimetidine group, 16 in the placebo group). For pruritus unrelieved by the study drug, bolus doses of naloxone hydrochloride 0.2 mg i.v. were administered at 30-minute intervals, if needed. Pruritus was assessed by two subjective rating scales and the number of naloxone doses needed for unrelieved pruritus. Using independent Student's t-tests, we identified no significant differences between the two groups. The mean numbers of naloxone boluses administered were 1.9 for placebo and 2.5 for cimetidine (p = 0.49). Our study demonstrates the importance of objectively evaluating the use of drugs for non-Food and Drug Administration-approved indications.