Combination paracetamol and ibuprofen for pain relief after oral surgery: a dose ranging study.

Purpose: Combined paracetamol and ibuprofen has been shown to be more effective than either constituent alone for acute pain in adults, but the dose-response has not been confirmed. The aim of this study was to define the analgesic dose-response relationship of different potential doses of a fixed dose combination containing paracetamol and ibuprofen after third molar surgery.

Methods: Patients aged 16 to 60 years with moderate or severe pain after the removal of at least two impacted third molars were randomised to receive double-blind study medication as two tablets every 6 h for 24 h of either of the following: two tablet, combination full dose (paracetamol 1000 mg and ibuprofen 300 mg); one tablet, combination half dose (paracetamol 500 mg and ibuprofen 150 mg); half a tablet, combination quarter dose (paracetamol 250 mg and ibuprofen 75 mg); or placebo. The primary outcome measure was the time-adjusted summed pain intensity difference over 24 h (SPID 24) calculated from the 100-mm VAS assessments collected over multiple time points for the study duration.

Results: Data from 159 patients were included in the analysis. Mean (SD) time-adjusted SPID over 24 h were full-dose combination 20.1 (18.0), half dose combination 20.4 (20.8), quarter dose combination 19.3 (20.0) and placebo 6.6 (19.8). There was a significant overall effect of dose (p = 0.002) on the primary outcome. Planned pairwise comparisons showed that all combination dose groups were superior to placebo (full dose vs. placebo p = 0.004, half dose vs. placebo p = 0.002, quarter dose vs. placebo p = 0.002). The overall effect of dose was also significant for maximum VAS pain intensity score (p = 0.048), response rate (p = 0.0094), percentage of participants requiring rescue (p = 0.025) and amount of rescue (p < 0.001). No significant dose effect was found for time to peak reduction in VAS or time to meaningful pain relief. The majority of adverse events recorded were of mild (52.75%) or moderate (40.16%) severity and not related (30.7%) or unlikely related (57.5%) to the study medication.

Conclusion: All doses of the combination provide safe superior pain relief to placebo in adult patients following third molar removal surgery.