Effects of Perioperative Pregabalin for Post-Craniotomy Pain

Inclusion Criteria: * Adults, 18 to 65 years (limited to 65 years to lower the risk of over-sedation for elderly patients) * Undergoing elective craniotomy (supratentorial or infratentorial) under general anaesthesia for: biopsy or resection of a tumour, clipping of an unruptured aneurysm, or excision of an arteriovenous malformation * ASA physical status I-III Exclusion Criteria: * predicted need for prolonged post-operative ventilation (\> 12 hours) * chronic pain secondary to previous craniotomy * known adverse reaction to drugs used (gabapentin, pregabalin, hydromorphone, and/or acetaminophen) * prior use of pregabalin or gabapentin (within 2 weeks before surgery) * current history of moderate to severe headaches (NRS ≥ 4) related to intracranial pathology (tumour pain) since it may be difficult to discriminate between ongoing tumour pain and surgery-related post-operative pain * current history of migraines * pre-existing chronic pain requiring chronic opioid use (30mg morphine equivalent within 4 weeks of surgery) * currently taking any drug that could interact with pregabalin * current history of alcohol or recreational drug abuse * known or suspected addiction to narcotic substances or chronic narcotic use in the last 2 weeks * history of malignant hyperthermia (contraindicates the anaesthesia protocol of this study) * history of angioedema * Body Mass Index ≤ 18.4 or ≥ 35 * history of untreated obstructive sleep apnea * any condition that would contraindicate the use of patient-controlled analgesia (PCA) * lacks fluency in English * pre-existing renal impairment (for pregabalin elimination) * pregnancy