Interaction of rifampicin with piroxicam and prednisolone

ABSTRACT

The effect of rifampicin on the anti-inflammatory activities of both piroxicam and prednisolone was studied using two models of inflammation. Carrageenin-induced rat hind paw edema model revealed that intraperitoneal administration of rifampicin [50 mg/kg] in combination with piroxicam [5 mg/kg] significantly diminished the anti-inflammatory effect of the tater. The anti-inflammatory activity of prednisolone [10 mg/kg] in this model was only slightly implantation. Sponge implantation-induced granuloma model showed that the intraperitoneal administration of rifampicin [50 mg/kg] in combination with piroxicam [5 mg/kg] or prednisolone [10 mg/kg] once daily for 8 days resulted in a significant reduction in the anti- inflammatory activities of both piroxicam and prednisolone. The effect of piroxicam and prednisolone on the bactericidal activity of rifampicin was also evaluated both in broth and in rat serum after i.p. injection. In vitro broth studies of the bactericidal activity of rifampicin [5 mug/ml] or prednisolone [3 mug/ml] against Staphylococcus aureus did not show any significant difference between the killing rats of these regimens. Studies on rat sera showed that the bactericidal activity of sera of rats injected with rifampicin [50 mg/kg i.p.] alone against Staphylococcus aureus was significantly higher than those sera of rats received rifampicin in combination with prednisolone [10 mg/kg]. The anti-staphylococcal activity of rifampicin in rat serum was not significantly affected by concomitant administration of piroxicam [5 mg/kg i.p.]