Antinociceptive and antiinflammatory effects of ketoprofen are potentiated by a vitamin B mixture in the rat

Ketoprofen is a nonsteroidal antiinflammatory drug (NSAID) widely used in therapeutics. However, gastrointestinal toxicity may limit its use. To reduce the requirements of NSAIDs and hence their toxicity, these compounds have been combined with several drugs. B vitamins increase the analgesic activity of NSAIDs, but conflicting results have been obtained. The purpose of this study was to establish whether a vitamin B mixture can increase the antinociceptive effect of ketoprofen in the thermal paw stimulation model and in antiinflammatory activity in carrageenan-induced paw edema in the rat. Ketoprofen produced a dose-dependent antinociception, whereas a mixture of B vitamins produced a very limited antinociceptive effect. However, B vitamins were able to increase the antinociceptive effect of ketoprofen, reaching effects similar to those obtained with the maximal dose of ketoprofen tested. Ketoprofen produced a dose-dependent antiinflammatory activity and B vitamins also produced significant antiinflammatory effects. When ketoprofen was combined with a mixture of B vitamins, an increase in the antiinflammatory action was observed. These results indicate that coadministration of B vitamins with ketoprofen can increase both antihyperalgesic and antiinflammatory effects. Thus, B vitamins are effective as analgesic adjuvants in the models tested.