[Drug interactions between glucocorticoids and other drugs]

Various interaction mechanisms between glucocorticoids and other drugs are reviewed. Among these interactions, the effects of liver microsomal enzyme-inducing agents such as anticonvulsants (barbiturates and phenytoin) and rifampicin, on the glucocorticoid metabolism are the most prominent and important. We reported on a patient with polymyositis under prednisolone therapy, who relapsed after concurrent use of rifampicin. Marked differences in the degrees of accelerated metabolism among glucocorticoids, the order of which was dexamethasone, prednisolone and hydrocortisone, were observed in the patients under rifampicin therapy. It may be concluded that careful attention to the drug interactions between glucocorticoids and other drugs is required in the clinical management.