The investigators hypothesize that perioperative oral administration of pregabalin would reduce postoperative pain and produce reduction in postoperative opioid consumption after anterior cruciate ligament (ACL) reconstruction . Patients are randomly assign to 1 of 2 groups. The placebo group receive placebo capsules 1 hour before surgery and 12 hours after initial dose. The pregabalin group receive pregabalin 150 mg, respectively at the same points.

Inclusion Criteria:

• age between 20-65 years
• physical condition type I or II in ASA (American Society of Anesthesiology)

Exclusion Criteria:

• patients of ASA classification 3 or more
• with a history of cardiovascular or respiratory disease
• dizziness or frequent headache
• active alcohol or drug usage,
• intake of any analgesics daily or 48 hours before surgery
• impaired renal and/or hepatic function