Ninety minutes before surgery, subjects will be allocated randomly into three groups by drawing sequentially numbered sealed opaque envelopes containing a software-generated randomization code to the placebo (n = 45), pregabalin 150 mg (n = 45) and the pregabalin 300 mg (n = 45) groups. The placebo and pregabalin capsules look identical and will be prepared by a local pharmacy. An anaesthesiologist not otherwise involved in the study and who will be blinded to treatment regimen will provide perioperative care. An independent investigator will collect perioperative data. All staff in the operating room will be unaware of patient allocation group.