Purpose: Postoperative pain control is often inadequate in low-income countries such as Rwanda, prompting the search for an inexpensive improvement. A randomized controlled trial was conducted to study the use of subcutaneous ketamine for the management of postoperative pain in patients undergoing major surgery in Kigali, Rwanda. Methods: Fifty-nine patients undergoing major abdominal, head and neck, plastic, or gynecological surgeries were studied. In addition to standard care, patients received five subcutaneous injections of ketamine 1 mg·kg −1 (ketamine group, n = 30) or normal saline (placebo group, n = 29) during the postoperative period. The first injection was administered in the postanesthesia care unit and then every 12 hr thereafter starting at 20:00 on the day of surgery. Pain was assessed three times per day using an 11-point verbal response scale. Patients were also assessed for side effects, including nausea and vomiting, hallucinations, nightmares, sedation, hypertension, and seizures. Results: The mean (SD) overall postoperative pain scale score was higher in the control group than in the ketamine group [4.8 (1.7) vs 3.7 (1.5), respectively; difference of means, 1.1; 95% confidence interval [CI], 0.3 to 1.9; P = 0.009]. Brief hallucinations (ketamine group, 11 patients; placebo group, 0 patients; risk difference, 0.37; 95% CI, 0.18 to 0.54; P < 0.001) were associated with ketamine administration. Conclusions: Results of this study in Kigali, Rwanda showed that subcutaneous administration of ketamine 1 mg·kg −1 twice daily, in addition to standard postoperative care, produced a small improvement in postoperative pain but resulted in more minor side effects Trial registration: www.clinicaltrials.gov (NCT02514122). Registered 31 July 2015.
