Analgesic efficacy of amfenac, aspirin and placebo after extraction of impacted teeth.

Amfenac, an arylacetic acid derivative, is a new investigational, nonsteroidal antiinflammatory agent that has exhibited analgesic properties superior to those of phenylbutazone in animals. This double-blind, randomized, parallel study was an early clinical trial to evaluate the analgesic efficacy of one oral dose of amfenac 100 mg compared to aspirin 600 mg and placebo in 120 subjects with moderate to severe pain after extraction of impacted molar teeth. Self-evaluated subjective pain intensity and relief reports for 4 hours were used as indexes of response. Analgesic effects of amfenac were significantly superior to those of placebo (p less than 0.001) and aspirin (p less than 0.05) by most measurements. Aspirin 600 mg was superior to placebo based on total pain relief and global scores (p less than 0.05). Compared with aspirin 600 mg, amfenac 100 mg provided greater and faster analgesia, lasting at least for 4 hours. Ordinal pain intensity scores correlated well with the visual pain analog scale. Seven (17.5%) patients taking amfenac compared to 5 (12.5%) taking placebo reported minor adverse effects).