For the treatment of tuberculosis, it is administered daily for at least six months. Combination therapy is used to prevent the development of resistance and to shorten the length of treatment. Resistance of Mycobacterium tuberculosis to rifampicin develops quickly when it is used without another antibiotic, with laboratory estimates of resistance rates from 10−7 to 10−10 per tuberculosis bacterium per generation.Rifampicin can be used alone in patients with latent tuberculosis infections to prevent or delay the development of active disease because only small numbers of bacteria are present. A Cochrane review found no difference in efficacy between a 3- to 4-month regimen of rifampicin and a 6-month regimen of isoniazid for preventing active tuberculosis in patients not infected with HIV, and patients who received rifampicin had a lower rate of hepatotoxicity. However, the quality of the evidence was judged to be low. A shorter 2-month course of rifampicin and pyrazinamide had previously been recommended but is no longer recommended due to high rates of hepatotoxicity.Rifampicin should be taken on an empty stomach with a glass of water. It is generally taken either at least one hour before meals or two hours after meals.Rifampicin is also used to treat nontuberculous mycobacterial infections including leprosy (Hansens disease) and Mycobacterium kansasii.With multidrug therapy used as the standard treatment of Hansens disease, rifampicin is always used in combination with dapsone and clofazimine to avoid causing drug resistance.It is also used in the treatment of Mycobacterium ulcerans infections as associated with Buruli ulcer, usually in combination with clarithromycin or other antibiotics.
The Enterobacteriaceae, Acinetobacter species, and Pseudomonas species are intrinsically resistant to rifampicin.It has been used with amphotericin B in largely unsuccessful attempts to treat primary amoebic meningoencephalitis caused by Naegleria fowleri.Rifampicin can be used as monotherapy for a few days as prophylaxis against meningitis, but resistance develops quickly during long-term treatment of active infections, so the drug is always used against active infections in combination with other antibiotics.Rifampicin is relatively ineffective against spirochetes, which has led to its use as a selective agent capable of isolating them in materials being cultured in laboratories. Viruses
Rifampicin has some effectiveness against vaccinia virus. Pathogen susceptibility
The minimum inhibitory concentrations of rifampicin for several medically significant pathogens are:

Mycobacterium tuberculosis — 0.002 – 64 µg/ml
Mycobacterium bovis — 0.125 µg/ml
Staphylococcus aureus (methicillin resistant) — ≤ 0.006–256 µg/ml
Chlamydia pneumoniae — 0.005 µg/ml

Primary biliary cholangitis
Rifampicin is used to treat itchiness caused by primary biliary cholangitis. The treatment-related adverse effects include hepatotoxicity, nephrotoxicity, hemolysis, and interactions with other drugs. For those reasons as well as some ethical concerns regarding off-label use of antibiotics, rifampin as a very effective preventive antibiotic for meningitis, is not considered appropriate for itchiness. Hidradenitis suppurativa
Rifampicin with clindamycin has been used to treat the skin disease hidradenitis suppurativa. Adverse effects
The most serious adverse effect is hepatotoxicity, and people receiving it often undergo baseline and frequent liver function tests to detect early liver damage.The more common side effects include fever, gastrointestinal disturbances, rashes, and immunological reactions.