A Pilot Trial to Determine the Effective Dose of N-acetylcysteine for Opioid Reduction in Patients Undergoing Spine Surgery.

First 20 subjects: 5 participants will be randomized to each dose group (placebo, 50, 100, and 150 mg/kg) to estimate the dose response curve and to identify the optimal dose.

If the dose response curve is adequate and the optimal dose identified, 15 additional participants will be randomized to placebo and 15 to the optimal dose to estimate the difference in opioid consumption between participants on placebo vs. the optimal dose. (Total of 50 subjects with 20 from dose response curve and 30 to estimate the difference in opioid consumption.)

If the dose response curve is not adequate after the initial 20 subjects 5 per each dose group, then an additional 5 participants will be randomized and to each dose group (placebo, 50, 100, and 150 mg/kg) to estimate the dose response curve and to identify the optimal dose. Once the optimal dose is identified with these initial 40 patients, 10 additional participants will be randomized to placebo and 10 to the optimal dose to estimate the difference in opioid consumption between participants on placebo vs. the optimal dose. (60 patients total with 40 to create the dose response curve and 20 more to estimate the difference in opioid consumption.)

A sample size of 20 subjects per group (placebo and optimal dose) allows us to estimate a 95% confidence interval for the mean difference in opioid consumption with a width of + 0.64 standard deviations from the mean. 70 subjects may be enrolled to account for withdrawal but the study will be completed once 50 or 60 subjects (based on the number of subjects required to create the dose response curve) have completed the protocol.