Comparison of the effects of pregabalin and famotidine with pregabalin and diphenhydramine on postoperative abdominal pain

Objectives: Pain is one of the most significant problems, and its uncontrolled management can lead to complications such as increased blood pressure, myocardial ischemia, etc. An effective approach to control postoperative pain is preemptive pain management with a combination of drugs prior to surgery. The present study aims to compare the level of postoperative abdominal pain in patients receiving pregabalin and famotidine versus pregabalin and diphenhydramine. Materials and methods: In this double-blind clinical trial, a total of 34 candidates for abdominal surgery (laparotomy) with ASA physical status classification of 1 or 2 were enrolled from the patients referring to (XXX). They were divided into two groups of 17 (Group A: pregabalin and famotidine, Group B: pregabalin and diphenhydramine). The drugs were administered to the patients 2 h before the surgery. The patients' pain levels were measured using the Visual Analog Scale (VAS) at the recovery stage after complete consciousness and at 6, 12, and 24 h postoperatively. Additionally, the amount of analgesic consumed within the first 24 h after the surgery was recorded and compared between the two groups. Results: The average pain intensity score at 6 h postoperatively was (6 +/- 0.2) in patients who received pregabalin and diphenhydramine, and (7.1 +/- 0.1) in patients who received pregabalin and famotidine (p = 0.002). The average pain intensity score at 12 h postoperatively was (6.1 +/- 0.3) in patients who received pregabalin and famotidine, and (5.6 +/- 0.2) in patients who received pregabalin and diphenhydramine (p = 0.021). Furthermore, the average pain intensity score at 24 h postoperatively was (5.2 +/- 0.2) in patients who received pregabalin and famotidine, and (4.2 +/- 0.2) in patients who received pregabalin and diphenhydramine (p = 0.014). The results demonstrated that the pain intensity score decreased in all four measured time intervals in the overall patient population (p < 0.001), and this reduction was significantly different between the two groups (p = 0.002), with the final average pain score being lower in the group receiving pregabalin and diphenhydramine compared to the other group. Conclusion: The results of this study indicate that the use of drugs such as diphenhydramine and pregabalin as preemptive medications can be effective in controlling postoperative abdominal pain and reducing the consumption of analgesics in patients after abdominal surgery.