Dose- and time-related effect of troleandomycin on methylprednisolone elimination

Effects of varying doses of troleandomycin (TAO) on methylprednisolone disposition were examined in five steroid-dependent asthmatic patients. The characteristic reduction in methylprednisolone elimination in the presence of TAO after a 40 mg IV methylprednisolone was also present after methylprednisolone doses as low as 4 mg. In patients receiving continuous TAO on an every-other-day basis, inhibition of methylprednisolone elimination was impaired to a greater extent on the "day on" TAO than on the "day off" TAO. Methylprednisolone elimination on the day off TAO was still slower than that before TAO, however. TAO on a multiple-dose schedule resulted in greater reduction of methylprednisolone elimination than after a single TAO dose. These results suggest that TAO induces immediate and continued inhibition of methylprednisolone disposition.