Effects of single-dose gabapentin on postoperative pain and morphine consumption after cardiac surgery.

OBJECTIVE

The purpose of this study was to evaluate the analgesic effect of single-dose preoperative gabapentin on postoperative pain and morphine consumption after cardiac surgery.

DESIGN

A randomized, double-blind, placebo-controlled, clinical study.

SETTING

A single university hospital.

PARTICIPANTS

Sixty patients undergoing coronary artery bypass graft surgery.

INTERVENTIONS

Patients were randomly allocated into 2 groups preoperatively either to receive 600 mg of oral gabapentin (GABA) or placebo (PLA) 2 hours before the operation. After extubation, an anesthesiologist blinded to the groups recorded pain scores both at rest and with cough with a 10-point verbal rating scale and sedation scores at 2, 6, 12, 18, 24, and 48 hours. Cumulative morphine consumption and the incidence of side effects were recorded during the study period.

MEASUREMENTS AND MAIN RESULTS

The total morphine consumption was lower in the GABA group (6.7 ± 2.5 mg) than in the PLA group (15.5 ± 4.6 mg, p < 0.01). Pain scores at rest were significantly lower in the GABA group than in the PLA group throughout the study period (p < 0.05 in all measurement times). Pain scores at 2, 6, and 12 hours during coughing were significantly lower in the GABA group (p < 0.05). The number of oversedated patients was significantly higher in the GABA group at 2, 6, and 12 hours of study compared with PLA (p < 0.001 at 2 and 6 hours and p < 0.02 at 12 hours). The postoperative mechanical ventilation period was significantly prolonged in the GABA group (6.6 ± 1.2 hours) compared with the PLA group (5.5 ± 1 hours, p < 0.01). Nausea incidence was significantly lower in the GABA group (n = 9) than in the PLA group (n = 18, p = 0.02).

CONCLUSIONS

Oral GABA at a dose of 600 mg given before cardiac surgery significantly reduced postoperative morphine consumption and postoperative pain both at rest and with cough.