Analgesic Potentials of Preoperative Oral Pregabalin, Intravenous Magnesium Sulfate, and their Combination in Acute Postthoracotomy Pain

Objectives: The objective of this study was to investigate the effects of the preoperative combination of oral Pregabalin and intravenous (IV) magnesium sulfate as analgesic adjuvants in postthoracotomy pain. Patients and Methods: One hundred twenty patients with American Society of Anesthesiologists physical status II were allocated randomly into 1 of 4 groups. Group MP received 300 mg pregabalin orally and an IV infusion of magnesium sulfate 50 mg/kg mixed with 200 mL normal saline (NS); group P received 300 mg pregabalin orally and 200 mL NS infusion; group M received an IV infusion of magnesium sulfate 50 mg/kg mixed with 200 mL NS and a placebo capsule; and group C received placebo capsule and an IV infusion of 200 mL NS. All medications were given 1 hour before surgery in all groups. In the first 24 hours postoperatively, total morphine consumption, the Visual Analog Scale (0 to 10)-used as a pain measurement tool-and postoperative nausea and vomiting were assessed. Results: The total morphine consumption in the first 24 hours postoperatively decreased significantly in group MP (28.47 +/- 5.76 mg) compared with group P (33.97 +/- 6.34 mg), group M (40.87 +/- 4.4 mg), and group C (42.2 +/- 6.1 mg), respectively. VAS scores were in the accepted range (<= 4) in the 4 groups throughout the first 24 hours, as all patients were on patient-controlled analgesia. However, there was a statistically significant difference at 0 and 4 hours postoperatively in favor of groups MP and P. Postoperative nausea and vomiting decreased significantly in groups MP, P, and M in comparison with group C (P<0.001). Conclusions: The combined preoperative single dose of pregabalin and magnesium sulfate is an effective method for attenuating postoperative pain and total morphine consumption in patients undergoing thoracotomy.