Comparative effects of benoxaprofen and other anti-inflammatory drugs on bone damage in the adjuvant arthritic rat.

Benoxaprofen, a new nonsteroidal anti-inflammatory agent recently marketed as an an antirheumatic drug, has been reported to suppress leucocyte migration into inflammatory sites, possibly by its reported inhibition of leukotriene synthesis. Benoxaprofen is also a weak to moderate inhibitor of prostaglandin synthesis. The effect of benoxaprofen was examined on adjuvant-induced arthritis in rats by radiographic assessment of bone damage. The effect of benoxaprofen was compared to other nonsteroidal anti-inflammatory agents, considered to act primarily by the inhibition of synthesis and/or release of prostaglandins. Drugs were administered from the 15th to the 30th day after induction of the adjuvant disease ('established adjuvant'). Radiographs of adjuvant rats showed extensive bone damage that was markedly suppressed by 30-40 mg/kg of benoxaprofen. Benoxaprofen exerted a dose-related inhibition of bone damage. There was less suppression of bone damage by comparable doses of phenylbutazone, oxyphenbutazone, ibuprofen, fenbufen, naproxen, tolectin and sulindac. Indomethacin, piroxicam and flurbiprofen were nearly as effective but only in doses that produced adverse effects or death in rats. Benoxaprofen may modify the progression of the experimental arthritic disease through a suppression of leucocyte migration.