JOMS study: IV acetaminophen use results in no significant pain decrease in wisdom teeth patients

ROSEMONT, Ill. – Intravenous acetaminophen is not recommended to relieve pain after surgery in patients who have their wisdom teeth extracted, according to a new study.

However, this medication can be an additional resource for minimizing pain after surgery based on other studies indicating its effectiveness, researchers wrote in the study published in the July issue of the Journal of Oral and Maxillofacial Surgery – the official journal of the American Association of Oral and Maxillofacial Surgeons (AAOMS).

For the randomized, double-blind study, 72 patients diagnosed with partially erupted (partial bony) or not erupted (complete bony) impacted wisdom teeth were selected – 35 were in the group that received acetaminophen, and the others were in the placebo group.

Patients received a 15-minute infusion of acetaminophen or the placebo after surgery. The participants also received “standard-of-care” anesthetic drugs for wisdom teeth extraction and an inferior alveolar nerve block or local infiltration to numb the area. Using a 0-10 numerical rating scale, the participants were asked to rate their pain immediately after the procedure, and then again by phone four and 24 hours after surgery.

Researchers found “no statistically significant” decrease in pain in patients who received IV acetaminophen immediately, four hours or 24 hours after surgery. Immediately after surgery, both groups had a median pain score of zero, likely showing the anesthetic’s continuous effect and the block placement’s effectiveness in most patients, researchers concluded. In addition, with its quicker onset, the IV acetaminophen likely took effect before the block wore off, the study notes.

Researchers also found the median pain in both groups was 6.0 four hours after surgery, indicating pain intensified as the block wore off. A day after surgery, the average pain score was 3.8 in the acetaminophen group compared to 4.1 in the placebo group, as pain control improved in both groups, researchers wrote.

“Given our findings, continued research is necessary to examine ways to minimize postoperative pain after third molar extractions while minimizing potentially harmful side effects,” researchers wrote. “Future avenues of study looking at acetaminophen could examine the effect of preoperative acetaminophen and perform comparisons of oral and IV acetaminophen and scheduled oral acetaminophen postoperatively to optimize pain control and reduce opioid use in third molar extractions.”

Other studies have found that oral administration of acetaminophen resulted in significantly reduced pain after surgery, and IV acetaminophen and morphine are more effective than placebo for relieving pain, though acetaminophen is safer, researchers wrote.

The authors of “Use of Intravenous Acetaminophen in Postoperative Pain Management After Partial and Full Bony Impacted Third Molar Extractions: A Randomized Double-Blind Controlled Trial” are from the Department of Oral and Maxillofacial Surgery, School of Dental Medicine, Case Western Reserve University, Cleveland, Ohio: Isabel Atencio, DDS; Max Beushausen, DMD, MD; Andres Flores-Hidalgo, DDS; and Dale A. Baur, DDS, MD; and from the School of Dental Medicine, Case Western Reserve University: Nora Fitzgerald; and from the Department of Anesthesiology, Perioperative and Pain Medicine, School of Medicine, Stanford University, Stanford, Calif.: John J. Kowalczyk, MD.

The full article can be accessed at