To determine whether single preoperative administration of 2 different doses of pregabalin (75 and 150 mg) could decrease postoperative pain intensity and opioid consumption following posterior lumbar interbody fusion surgery.

Prospective, randomized, active placebo-controlled, double-blinded study.

Postoperative recovery area and patients' room.

Ninety-seven adult, American Society of Anesthesiologists physical status 1 and 2 patients.

Patients were randomly assigned to receive diazepam 5 mg as an active placebo (D5), pregabalin 75 mg (P75), or pregabalin 150 mg (P150). The study drug was orally administered 2 hours prior to surgery and a standard anesthetic technique was used. Postoperative pain was managed using intravenous patient-controlled analgesia with morphine.

The visual analog scale at rest was used to measure pain intensity immediately after extubation at the postanesthesia care unit, and then 2, 4, 6, 12, 18, 24, 36, and 48 hours after surgery. Morphine consumption and adverse effects were assessed until 48 hours after surgery.

The visual analog scale score at rest was lower in the P150 group than in the D5 group until 2 hours after surgery. Morphine consumption was lower in the P150 group than in the D5 from 0 to 12 hours after surgery.

Single preoperative administration of 150 mg of pregabalin 2 hours prior to surgery reduced postoperative pain intensity and morphine consumption compared with 5 mg diazepam in patients who underwent posterior lumbar interbody fusion.