Postoperative Pain After Abdominal Hysterectomy: A Randomized, Double-Blind, Controlled Trial Comparing the Effects of Tramadol and Gabapentin as Premedication

BACKGROUND: Uncontrolled postoperative pain, characteristic to abdominal hysterectomy, results in multiple complications. One of the methods for controlling postoperative pain is preemptive analgesia. Gabapentin and tramadol are both used for this purpose. OBJECTIVES: This study aims to compare the effects of tramadol and gabapentin, as premedication, in decreasing the pain after hysterectomy. PATIENTS AND METHODS: This clinical trial was performed on 120 eligible elective abdominal hysterectomy patients, divided in three groups of 40, receiving tramadol, gabapentin and placebo, respectively. Two hours before the surgery, the first group was given 300 mg gabapentin, the second one was given 100 mg tramadol, while the other group was given placebo, with 50 ml water. After the surgery, in case of visual analog pain scale (VAS) > 3, up to 3 mg of diclofenac suppository would be used. Pain score, nausea, vomiting, sedation, patient’s satisfaction and the number of meperidine administered during 24 hours (1 - 4 - 8 - 12 - 16 - 20 - 24 hours) were recorded. If patients had VAS > 3, despite using diclofenac, intravenous meperidine (0.25 mg/kg) would be prescribed. Data were analyzed using SPSS 21 software, chi-square test, general linear model and repeated measurement. RESULTS: The three groups were similar regarding age and length of surgery (up to 2 hours). The average VAS, in the placebo group, was higher than in the other two groups (P = 0.0001) and the average received doses of meperidine during 24-hour time were considerably higher in placebo group, compared to the other two groups (55.62 mg in placebo, 18.75 mg in gabapentin and 17.5 mg in tramadol groups, P = 0.0001). Nausea, vomiting and sedation, in the tramadol group, were higher than in the other two groups, although they were not significant. Patients’ dissatisfaction, in the placebo group, during initial hours, especially in the fourth hour, was higher (P = 0.0001). In the gabapentin and tramadol groups, the trend of changes in satisfaction score was similar. However, satisfaction in the gabapentin group, during the initial 4 hours was higher, in comparison to the tramadol group (P = 0.0001). CONCLUSIONS: This study revealed that prescribing gabapentin or tramadol, as premedication, was effective in reducing postoperative pain, without any concerning side-effects.