Rifampicin

Overview
Rifampicin (INN) (IPA: ) or rifampin (USAN) is a bactericidal antibiotic drug of the rifamycin group. It is a semisynthetic compound derived from Amycolatopsis rifamycinica  (formerly known as Amycolatopsis mediterranei and Streptomyces mediterranei). Rifampicin may be abbreviated RIF, RMP, RD, RA or R.

Indications
Rifampicin is typically used to treat Mycobacterium infections, including tuberculosis and leprosy; and also has a role in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) in combination with fusidic acid. It is used in prophylactic therapy against Neisseria meningitidis (meningococcal) infection.

It is also used to treat infection by Listeria species, Neisseria gonorrhoeae, Haemophilus influenzae and Legionella pneumophila. For these non-standard indications, sensitivity testing should be done (if possible) before starting rifampicin therapy. Rifampicin resistance develops quickly during treatment and rifampicin monotherapy should not be used to treat these infections — it should be used in combination with other antibiotics. With multidrug therapy (MDT) used as the standard treatment of leprosy, rifampicin is always used in combination with dapsone and clofazimine.

Enterobacteriaceae, Acinetobacter and Pseudomonas species are intrinsically resistant to rifampicin.

Mechanism of action
Rifampicin inhibits DNA-dependent RNA polymerase in bacterial cells by binding its beta-subunit, thus preventing transcription of messenger RNA (mRNA) and subsequent translation to proteins. Its lipophilic nature makes it a good candidate to treat the meningitis form of tuberculosis, which requires distribution to the central nervous system and penetration through the blood-brain barrier.

Adverse effects
Adverse effects are chiefly related to the drug's hepatotoxicity, and patients receiving rifampicin often undergo liver function tests including aspartate aminotransferase (AST).

The most common unwanted effects are fever, gastrointestinal disturbances, rashes and immunological reactions. Liver damage, associated with jaundice, has also been reported and in some rare cases has led to death.

Taking rifampicin can cause certain bodily fluids, such as urine and tears, to become orange-red in color, a benign but sometimes frightening side-effect. This may permanently stain soft contact lenses. It also may be excreted in breast milk, therefore breast feeding should be avoided.

Rifampicin is a potent inducer of hepatic cytochrome P450 enzymes (such as CYP2D6 and CYP3A4) and will increase the metabolism of many drugs that are cleared by the liver through this enzyme system. This results in numerous drug interactions such as reduced efficacy of hormonal contraception.

Preparations
In the U.S., rifampin is marketed as
 * Rifadin (Aventis),
 * Rifater (in combination with isoniazid and pyrazinamide) (Aventis),
 * Rimactane (Novartis).

In the UK, rifampicin is marketed as
 * Rifadin (Aventis),
 * Rimactane (Sandoz),
 * Rifater (in combination with isoniazid and pyrazinamide) (Aventis),
 * Rifinah (in combination with isoniazid) (Aventis)
 * Rimactazid (in combination with isoniazid) (Sandoz)

In Romania it is marketed as Sinerdol by Sicomed.

In Bulgaria it is marketed as Tubocin by Actavis/Balkanpharma.