Gabapentin May Relieve Post-Coronary Artery Bypass Graft Pain: A Double Blind Randomized Clinical Trial

Background: One of the most common complaints after coronary artery bypass graft (CABG) is post-operative pain. Gabapentin is an anticonvulsant and antineuralgic agent.

Objective: To evaluate the analgesic effect of preemptive gabapentin on post-operative pain and morphine consumption after cardiac surgery.

Methods: A double-blind randomized clinical trial was conducted on 60 male candidates for CABG. The patients were divided into two groups—the gabapentin (n=30) and the control group (n=30). The test group received 800 mg gabapentin orally two hours before the surgery followed by 400 mg of the drug two hours post-extubation. The control group received placebo instead. Then severity of pain was recorded according to an 11-point visual analog pain scale. The amount of morphine consumed, its side effects and hemodynamic changes were also recorded during and at 2, 6, 12, 18 and 24 hours after extubation.

Results: The mean±SD cumulative morphine consumption at the first 24 hours after extubation in gabapentin group was 0.9±1.5 mg while it was 1.5±4 mg for the control group. Therefore, gabapentin group consumed 38% less than the control group (P=0.01). The pain scores during rest and coughing at 2, 6, and 12 hours after extubation were also significantly lower in the gabapentin group compared with the control group (P=0.02). The mean±SD mechanical ventilation time was 5.4±1.7 hours for gabapentin group and 1.6±4.4 hours for the control group (P=0.035). The other variables including hemodynamic changes (HR, SBP and DBP), and incidence of nausea, vomiting and respiratory depression showed no significant difference between the studied groups within 24 hours after extubation.

Conclusion: Oral pre-medication with gabapentin before CABG significantly reduces post-operative pain and morphine consumption in adult cardiac surgery.