<qa>  How many doses of intravenous acetaminophen will be given eachThis is a single center, prospective, randomized controlled study. 60 subjects will be recruited see 6 Recruitment and Compensation below. On the day of surgery, subjects will be randomized to receive either the study intervention intravenous acetaminophen and placebo tablets or the control intervention intravenous saline and active acetaminophen tablets. The Investigational Drug Service will prepare each intervention package, which will include one intravenous and one oral medication dose. Only one of these routes will be active determined by randomization. Subjects will receive doses of both an intravenous and oral study drug every 6 hours in order to maintain blinding, and will receive a total of 4 doses of each at 0, 6, 12 and 18 hours. The dose of acetaminophen in all cases will be 1000 mg. The volume of intravenous acetaminophen and saline will be 100 mL. The oral dose will consist of two 2 tablets of 500 mg each or two matching placebo tablets. 