Prophylactic diphenhydramine attenuates postoperative catheter-related bladder discomfort in patients undergoing gynecologic laparoscopic surgery: a randomized double-blind clinical study

Background To evaluate the effectiveness of diphenhydramine, an antihistamine with anti-muscarinic properties, for prevention of postoperative catheter-related bladder discomfort (CRBD). Methods Ninety-six ASA physical status I and II adult female patients (20-60 years) scheduled for elective gynecologic laparoscopic surgery were included. Patients were randomized into two groups of 48 patients each. All patients received a detailed preoperative explanation of the possible consequences of CRBD. The control group received normal saline 2 ml, whereas the diphenhydramine group received diphenhydramine 30 mg intravenously after induction of general anesthesia. Then, all patients were catheterized with a 14F Foley catheter and the balloon was inflated with 10 ml of distilled water. All patients who complained of CRBD in the postoperative room were appeased with nursing. Ketorolac 30 mg was used as the rescue drug on patients' request or when the patient was evaluated as having moderate or severe CRBD. Bladder discomfort and its severity were assessed at 1, 2 and 6 h postoperatively. The severity of CRBD was graded as none, mild, moderate and severe. Adverse effects of diphenhydramine such as sedation, dry mouth or GI upset were recorded. Results The incidence of CRBD was lower in the diphenhydramine group compared with the control group at 2 h (34.8 vs. 58.7%, p = 0.02) and 6 h (23.9 vs. 56.5%, p < 0.01) postoperatively. Diphenhydramine treatment also reduced the severity of CRBD at 6 h postoperatively (p = 0.01). Moreover, the request for rescue for CRBD was lower in diphenhydramine group at 2 h (8.7 vs. 26.1%, p = 0.03). There were no significant differences in side effects, such as sedation, dry mouth or gastrointestinal upset between the two groups (p > 0.05). Conclusion Prophylactic diphenhydramine 30 mg at induction of general anesthesia reduced the incidence and severity of postoperative bladder discomfort without significant side effects in patients receiving gynecologic laparoscopic surgery.