Effect of Intravenous Patient Controlled Ketamine Analgesiaon Postoperative Pain in Opium Abusers

BACKGROUND: Acutepostoperative pain is among the worst experience that patient scan undergo, and many analgesics have been used to suppress it; especially in chronic opium abusers. Ketamine is an N-methyl-D-aspartate antagonist analgesic, having both anesthetic and analgesic properties, which are not affected to the same extent in chronic opium abusers. OBJECTIVES: In this study, we assessed the analgesic effects of ketamine added to morphine as a patient-controlled analgesia method for acute pain management, compared with a placebo, inchronic maleopium abusers. PATIENTS AND METHODS: After institutional review board approval for ethical considerations, a randomized double-blinded placebo controlled clinical trial was conducted. A total of 140 male patients aged 18-65 years, undergoing orthopedic surgery, were entered into the study after matching inclusion and exclusion criteria. All patients received the same anesthesia method; while the first group received ketamine (1mg/mL) and morphine (0.5 mg/mL) as a patient-controlled analgesia (70 patients), the second group received morphine (0.5 mg/mL) plus normal saline (70 patients). P value less than 0.05 was considered statistically significant. RESULTS: The ketamine and morphine group of patients experienced less postoperative pain and required less postoperative rescue analgesia. However, the unwanted postoperative side effects were nearly the same; although increased levels of postoperative nausea and vomiting were observed in the ketamine and morphine group CONCLUSIONS: This study demonstrated improved analgesic effects after using intravenous patient controlled analgesia with ketamine on postoperative pain in opium abusers.