Baseline pain and response to analgesic medications in the postsurgery dental pain model

In designing clinical trials for the treatment of acute pain, enrollment of patients with moderate to severe pain is recommended even when the desired indication is treatment of mild pain. To test this approach, the authors explored the results of two studies that had the same standard placebo-controlled, parallel-group design and that compared the study medication to a single dose of ibuprofen 400 mg. One study had 25 subjects, the other 50 in its ibuprofen arm. Subjects indicating moderate or severe pain (on a scale ranging from 0 = none, 1 = mild, 2 = moderate, 3 = severe) following a surgical extraction of two or more third molars were enrolled. There was a difference between the ibuprofen groups in these two studies in average baseline pain intensity (PI) (2.88 +/- 0.33 vs. 2.26 +/- 0.44). In the higher baseline group, PI decreased faster, achieving lower levels of PI that were maintained for the rest of the study period. The results of pain relief measurements paralleled those of PI. The authors conclude that including patients with a higher degree of baseline pain in the postoperative dental pain model has the potential to increase discrimination of analgesic properties of new drugs. Journal of Clinical Pharmacology, 2000;40:133-137 (C)2000 the American College of Clinical Pharmacology.