Rifampicin reduces effectiveness and bioavailability of prednisolone.

Abstract

IntroductionRifampicin is an inducer of the hepatic mixed function oxygenase enzymes involved in drug metabolism.' 2 Needle biopsy specimens of the liver from patients receiving rifampicin show an increase in cytochrome P4503 and proliferation of smooth endoplasmic reticulum in the hepatocytes.4 Rifampicin induces its own metabolism' during continuous treatment as demonstrated by a shortened half life. In addition, rifampicin can accelerate the elimination of the contraceptive pill,6 leading to menstrual disturbance and unwanted pregnancy. Tolbutamide, hexobarbitone,7 and oral anticoagulants8 are other drugs whose metabolism is similarly affected. Deterioration in renal9 and allograft function'0 associated with concomitant rifampicin treatment may be cited as indirect evidence of the effect of this drug on steroid metabolism.We report on two patients with respiratory disease in whom rifampicin affected metabolism of steroids; and we describe a study of the effects of rifampicin on the pharmacokinetics of prednisolone in seven patients.

Rifampicin Is Not an Activator of Glucocorticoid Receptor

“…Oxidation of steroids by cytochrome P450 most likely also accounts for the insufficient suppression of cortisol by dexamethasone in patients treated with rifampicin (Keven et al, 1998). According to the findings reported herein, the induction of cytochrome P450 3A genes by rifampicin and the subsequent oxidation of steroids and other compounds (Edwards et al, 1974;Elansary and Earis, 1983;McAllister et al, 1983) cannot be explained by activation of GR. Instead, these effects probably are mediated by recently described nuclear receptors termed pregnane X receptor (Kliewer et al, 1998(Kliewer et al, , 1999, or hPAR (Bertilsson et al, 1998)).…”

Pitfalls in the management of TB-associated uveitis

“…Rifampicin has been shown to reduce the bio-availability of prednisolone by 66%. 9 In all the four cases, these reactions resolved by adding/increasing corticosteroid therapy.…”

Mycobacterium abscessus Infections in Lung Transplant Recipients: The International Experience

“…12,14 Potentially unpleasant side effects may also threaten compliance with long-term treatment. Monitoring of clinical toxicities and drug levels is essential to minimize complications.…”