Effect of Oral Tizanidine on Postoperative Pain after Perianal Surgery

Alpha 2 adrenergic agonist such as tizanidine and clonidine have sedative and analgesic effects that can be effective as premedication for the general or spinal anesthesia. Tizanidine is a clonidine derivative that has the same effects. The purpose of this study was to evaluate the analgesic efficacy of oral tizanidine in preventing pain after anorectal surgery under spinal anesthesia. This double blind and clinical trial study was carried out on 60 male patients scheduled for anorectal surgery under spinal anesthesia. The patients were randomized into two groups: control group and tizanidine group. The control group received placebo and tizanidine group received 4mg of oral tizanidine as premedication 60 minutes before arrival in the operating room. The patients in the two groups received lidocaine 50 mg intrathecally. Meperidine consumption، duration of postoperative analgesia and side effects were studied in all patients. (IRCT: 201210315381N3) The mean age was the same in two groups. The duration of analgesia was 332. 50±9. 62 and 144. 19±5. 16 minutes in the tizanidine group and control group، respectively (p<0. 001). The meperidine consumption was 26. 67±15. 99 and 42. 17±20. 62 mg in tizanidine group and control group، respectively that the difference was statistically significant (p=0. 002). This study showed that preoperative oral tizanidine improved the severity of postoperative analgesia without increasing the side effects.