rifampicine

Rifampicin, also spelled rifampicine, is a broad‑spectrum antibiotic of the rifamycin class. It is produced by actinobacteria of the genus Amycolatopsis and is bactericidal by inhibiting the beta subunit of bacterial DNA-dependent RNA polymerase, thereby blocking RNA synthesis and transcription.

Rifampicin is a cornerstone of therapy for active tuberculosis and for prevention of TB in exposed individuals when used in combination with other antituberculous drugs. It is also used for prophylaxis against Neisseria meningitidis and Haemophilus influenzae type b infections after exposure and in various other infections depending on susceptibility. Because resistance can develop rapidly when rifampicin is used alone, it is almost always given with other agents. Its activity covers the Mycobacterium tuberculosis complex, some atypical mycobacteria, and many Gram‑positive cocci; it has variable activity against Gram‑negatives and limited activity against many anaerobes. It is not reliably active as monotherapy for most infections.

Rifampicin can be administered orally or by injection, with good absorption and wide distribution, including into tissues and inflamed meninges; it penetrates the CSF when meninges are inflamed. It is primarily hepatically metabolized and is a potent inducer of hepatic drug‑metabolizing enzymes (notably the cytochrome P450 system), which can reduce levels of many coadministered drugs. Excretion is mainly via bile. Adverse effects include hepatotoxicity, hypersensitivity, GI upset, rash, and flu‑like symptoms. A harmless orange‑red discoloration of urine, tears, and other body fluids may occur. Due to drug interactions, rifampicin requires careful monitoring with medications such as oral contraceptives, anticoagulants, and certain antiretrovirals.

Resistance emerges rapidly if used as monotherapy, typically via mutations in the rpoB gene. Brand names include Rifadin and Rimactane in various markets.