Results: Overall, 25.1% of patients received intravenous acetaminophen, of whom 48.0% (n = 21,878) received 1 dose on the day of surgery. In adjusted analyses, particularly more than 1 dose of intravenous acetaminophen (versus nonuse) on postoperative day 1 was associated with a −12.4% (99.5% CI, −15.2 to −9.4%) change in opioid utilization. In comparison, a stronger reduction was seen in those receiving more than 1 oral acetaminophen dose: −22.6% (99.5% CI, −26.2 to −18.9%). Unadjusted group medians were 550 and 490 oral morphine equivalents, respectively. Intravenous versus oral differences were less pronounced among those receiving more than 1 acetaminophen dose on the day of surgery: −8.0% (99.5% CI, −11.0 to −4.9%) median 499 oral morphine equivalents versus −8.7% (99.5% CI, −14.4 to −2.7%) median 445 oral morphine equivalents, respectively; all statistically significant, but none clinically significant. Comparable outcome patterns existed for opioid-related adverse effects.
Conclusions: The demonstrated marginal effects do not support routine use of intravenous acetaminophen given alternative nonopioid analgesic options.