Scheduled Intravenous Acetaminophen Improves Patient Satisfaction with Postcraniotomy Pain Management: A Prospective, Randomized, Placebo-controlled, Double-blind Study

Background: Postcraniotomy pain can be difficult to manage with opioids due to opioid-related side effects, including drowsiness, nausea/vomiting, confusion, and pupillary changes, potentially masking the signs of postoperative neurological deterioration. Intravenous (IV) acetaminophen, a nonopioid analgesic, has been reported to have opioid-sparing effects after abdominal and orthopedic surgeries. This study investigates whether IV acetaminophen has similar effects after craniotomy. Materials and Methods: In this prospective, randomized, placebo-controlled, double-blind clinical trial, 100 adult patients scheduled to undergo supratentorial craniotomy for excision of a brain mass were randomized to receive either IV acetaminophen or placebo preincision and then every 6 hours for a total of 24 hours after surgery. Total 24-hour opioid consumption, pain scores, satisfaction with overall pain management, time to meet postanesthesia care unit discharge criteria, and incidence of opioid-related side effects were compared. Results: There was no difference in the 24-hour postoperative opioid consumption in morphine equivalents between the IV acetaminophen group (median, 11 mg; n=45) and the placebo group (median, 10.1 mg; n=41). No statistically significant difference of visual analog scale pain score was observed between 2 treatment groups. Patient satisfaction with overall postoperative pain management was significantly higher in the IV acetaminophen group than the placebo group on a 1 to 10 scale (8.1±0.4 vs. 6.9±0.4; P=0.03). There was no significant difference in secondary outcomes, including the incidence of opioid-related side effects. Conclusions: IV acetaminophen, as adjunctive therapy for craniotomy procedures, did not show an opioid-sparing effect in patients for the 24 hours after craniotomy; however, it was associated with improved patient satisfaction regarding overall pain control.