The effect of premedication with oral memantine on pain control after orthopedic surgery

Aim and Memantine is one of NMDA receptor antagonists with a rapid onset and limited side effects; its inhibitory effects on neuropathic pain has mentioned while using before nerve injury. Few studies were done on evaluating oral memantine effects on acute post-orthopedic surgery pain. Methods and Materials: In a double blind clinical trial, 60 patients with ASAI, II and upper limb fracture in two groups were enrolled in this study. After signing informed consent by the patients, 1 hour before surgery 20mg memantine prescribed for case group and control group received placebo. The patients received fentanyl and midazolam as premedication then anesthesia induction with propofol and cisatracurium performned. Maintenance of anesthesia was propofol and remifentanil. Pain score with Visual Analogue Scale (VAS)and sedation score measured and recorded in recovery and 6,8,24,36 and48 hours later. Also total dose of opioid consumption and nausea and vomiting incidence was measured. No demographic differences exist between them. Pain score in recovery and 6, 24 hours later were lower in case group. Sedation score was significantly different in hour 24(P=0.04) Morphine dosage in case group was lower in recovery (P=0.01)Incidence of nausea and vomiting was not different between groups. Prescribing 20 mg memantine 1 hour before surgery, has been effective on pain reduction, also could decrease morphine demands in recovery.