The study is to observe the effects of gabapentin premedication on postoperative pain,vomiting and nausea in patients undergoing neurosurgery. 100 neurosurgical patients are randomized into groups gabapentin(GG) or placebo(GP). Patients are given gabapentin or placebo orally the night before operation day and 2hours before surgery,respectively.The investigators hypothesized that lower incidence of postoperative pain,vomiting and nausea be observed in GG than GP.

This is a random, double-blind study. In GG, patients are given gabapentin 600mg orally at the night and 2hours before surgery, respectively. In PG, vitamine pills are given instead.Total intravenous anesthesia is applied for all patients. 1hour, 2hours,1day, 2days, 3months and 6months after surgery, patients are evaluated for pain (VAS) and incidence of PONV. In addition,Glasgow Score, Ramsay Score and other gabapentin-related effects, such as somnolence,dizzy or dry mouth are also observed.The incidence of persistent pain and neuropathic pain was assessed at the 3-mo and 6-mo postoperative evaluation.

Inclusion Criteria:

• 18-65 years old, ASA physical status I or II, BMI<30
• Scheduled for elective craniotomy
• Cooperative and given informed consent in person

Exclusion Criteria:

• History of mental or psychiatric disorders
• Pregnant or lactating female
• History of systemic malignant tumor or diabetes
• Previously treated with this protocol or participated in another experimental study within previous 30 days
• Suspected history of allergic reaction or intolerance to gabapentin or other anesthetic agents in this study
• History of alcohol abuse and/or drug abuse within previous one year