Analgesic Efficacy of an Acetaminophen/Ibuprofen Fixed-dose Combination in Moderate to Severe Postoperative Dental Pain: A Randomized, Double-blind, Parallel-group, Placebo-controlled Trial

Purpose: Acute pain is a significant burden to the individual and to society. There is a clear need for a pain medication that provides improved analgesia over common analgesics, without compromising tolerability. The goal of this study was to determine the efficacy of a new fixed-dose combination of acetaminophen 975 mg and ibuprofen 292.5 mg (FDC 975/292.5) relative to acetaminophen or ibuprofen monotherapy, or placebo.

Methods: This prospective, multicenter, randomized, double-blind, placebo-controlled, Phase III trial included 408 adult volunteers aged 18 to 60 years experiencing moderate to severe pain after surgical removal of at least 2 impacted third molars. Subjects were randomized in a 3:3:3:2 ratio to the following interventions: FDC 975/292.5, acetaminophen 975 mg, ibuprofen 292.5 mg, and placebo. Self-reported pain intensity scores were recorded over a 48-hour double-blind treatment period using a 100-mm visual analog scale. In addition, time to perceptible and meaningful pain relief was assessed by using the two-stopwatch method; use of rescue medication (oxycodone) was recorded; and patients rated their pain relief on a 5-point categorical scale. All adverse events during the 30-day study period were assessed.

Findings: The majority of participants were female (67.4%) and white (90.0%), with a mean age of 24.8 years. Demographic and baseline characteristics were balanced across treatment groups, with a mean baseline pain score of 56.4 mm. The primary end point was the time-adjusted sum of pain intensity differences over 48 hours, which was found to be significantly greater for FDC 975/292.5 than for both monotherapies and placebo (all, P < 0.001). The robustness of the procedures used in the calculation of the primary end point was confirmed in a series of sensitivity analyses. Statistical superiority of the combination was evident in all secondary end points (time to meaningful pain relief, maximum pain score, response rate, participants using supplementary analgesia, time to rescue, oxycodone consumption, and categorical pain relief score) with the exception of time to perceptible pain relief versus monotherapies and the time to peak response versus ibuprofen. The percentage of patients reporting adverse events was 37.3% in the FDC 975/292.5 group, with no significant differences between treatment groups. Nausea was the most common adverse event across all groups.

Implications: Overall, the fixed-dose combination of acetaminophen and ibuprofen provided greater and more rapid analgesia than comparable doses of either agent alone or placebo in adults after removal of impacted third molars. ClinicalTrials.gov identifier: NCT01420653.