Rifampin for Tuberculosis

Rifampin is used to treat all forms of tuberculosis, together with other TB drugs. It is also used alone for 4 months for inactive TB, and to clear meningococcal germs from carriers without symptoms. Urine, sweat, tears and saliva turn orange while you take it, a change CDC called harmless in 2025³. The label rules it out as a treatment for meningococcal infection itself, and keeps it for carriers only¹. To slow drug resistance, the label limits its use to infections proven or strongly suspected to come from bacteria it kills¹. CDC guidance from 2025 recommends 4R for HIV-negative children and adults of any age². CDC in 2025 recommended it as well for people who cannot tolerate isoniazid or were exposed to isoniazid-resistant TB². Inactive TB, known as latent TB infection, is not contagious, as CDC stated in 2025.

Its other side effects need more attention than the color change. The full list of rifampin side effects shows which ones to report.

Rifampin works by blocking DNA-dependent RNA polymerase, an enzyme inside the TB bacterium. The drug label names this as its action against Mycobacterium tuberculosis. A single mutation in that enzyme can make the germ resistant, so rifampin is paired with other drugs for TB disease¹. In lab tests, it kills TB germs that grow slowly or only in bursts¹. After a 600 mg dose, blood levels peak at an average of 7 mcg/mL, ranging from 4 to 32¹. Food cuts absorption by about 30%, which is why the label asks for an empty stomach¹. About 80% of the drug in the blood is bound to proteins¹. It reaches working levels in many organs and body fluids, including the fluid around the brain and spinal cord¹. Its half-life averages 3.35 hours after a 600 mg dose¹. It leaves mainly through the bile, and up to 30% of a dose passes in the urine¹. A CDC lab guide from 2024 says over 95% of rifampin-resistant strains carry one change in a short stretch of rpoB. Rapid lab tests read that stretch to spot resistance in the bacterium behind tuberculosis.

Rifampin belongs to the rifamycin class of antibiotics, made in part from rifamycin SV. Rifapentine, used in the 3HP regimen, is in the same class. Rifamycins form the backbone of the shortest TB regimens, which are 3HP, 4R and 3HR². In pure form, rifampin is a red-brown crystalline powder with the formula C43H58N4O12¹. It barely dissolves in water at neutral pH¹. StatPearls (2023) says it acts against mycobacteria and many gram-positive germs⁶. It reaches some gram-negative germs as well, such as Neisseria meningitidis⁶. The wider list of medications that treat TB shows where each drug fits.

Rifampin is sold as a generic and under the brand name Rifadin. Outside the US it is often called rifampicin, the same drug under another name. Rifaximin has a similar name, yet it is a different drug. It belongs to the rifamycin class too, but less than 0.4% of it shows up in blood and urine. For that reason rifaximin works mainly in the gut, according to its Xifaxan label. SingleCare lists Rifadin IV as the brand name of the injectable form. CDC tables from 2025 shorten rifampin to RIF². Regimen names use the letter R for it, as in 4R and 3HR². The page on rifaximin vs rifampin sets the two drugs apart.

Rifampin is part of the standard 6-month RIPE regimen for active TB, and of 4R and 3HR for inactive TB. In RIPE, it is taken with three other drugs for 2 months, then with isoniazid alone for 4 more.

WHO in 2026 called rifampicin and isoniazid the two most effective first-line TB drugs. CDC guidance from 2025 defines MDR TB as TB resistant to at least isoniazid and rifampin, which needs other drugs⁸. CDC guidance from 2025 recommends 3HR for people with HIV on some antiretroviral combinations, where 4R is not advised². The page on drug-resistant tuberculosis covers the regimens used instead.

You should take rifampin once a day on an empty stomach, 1 hour before or 2 hours after a meal, with water. Take it at least 1 hour before any antacid, which can lower how much is absorbed.

• Take it at the same time each day³.
• If you miss a dose, skip it, take the next one and tell your provider³.
• Do not stop the course early³.

Keep the capsules at 77°F (25°C), with short spells between 59 and 86°F allowed¹. For active TB disease, CDC guidance from 2025 calls watched dosing the standard of care⁴. Under directly observed therapy, a health worker sees each dose taken, in person or by video⁴.

The usual adult rifampin dose for TB is 10 mg per kilogram once a day, up to 600 mg. Children take 10 to 20 mg per kilogram a day, also up to 600 mg. It comes as 150 mg and 300 mg capsules¹. In 4R it is taken daily for 4 months, and in RIPE for the full 6 months². CDC guidance from 2025 gives children 15 to 20 mg per kilogram in 4R and 3HR².

The four-drug plan for active disease is laid out in RIPE therapy for tuberculosis.

Rifampin comes as 150 mg and 300 mg capsules, and as a 600 mg powder for infusion into a vein. In one generic brand, the capsules have a dark red cap and a light red body around reddish-brown powder. The IV form is used for TB when the drug cannot be taken by mouth⁷. It goes only into a vein, never into a muscle or under the skin⁷. Each IV dose runs over 30 minutes to 3 hours⁷. For people who find capsules hard to swallow, a pharmacist can mix the contents into a 10 mg/mL liquid¹. One of four syrups is used, and the liquid keeps for 4 weeks at room temperature or in the refrigerator¹.

Rifampin lowers the levels of many other medicines in the body, so they work less well. It may make birth control pills and other hormonal birth control less reliable. It must not be taken with several HIV medicines, praziquantel or lurasidone¹. It lowers the levels of warfarin, digoxin, tacrolimus, oxycodone and methadone¹. With methadone, that drop can bring on withdrawal symptoms¹. CDC guidance from 2025 advises people on hormonal birth control to add or switch to a barrier method². StatPearls (2023) says lower levels of glyburide and glipizide, two diabetes pills, can worsen blood sugar control⁶. The label says to stop rifampin 4 weeks before taking praziquantel, a worm medicine¹. The full guide to rifampin drug interactions names more medicines.

Yes, rifampin is a strong inducer of liver enzymes, above all CYP3A4, so many drugs are cleared faster. The drug label calls it a well characterized and potent inducer of enzymes and drug transporters. It induces CYP1A2, 2B6, 2C8, 2C9, 2C19 and 3A4, and the transporter P-glycoprotein¹. As an inducer rather than an inhibitor, it lowers the levels of most drugs it affects instead of raising them¹. StatPearls (2023) says the effect takes about a week to build⁶. It then lasts nearly 2 weeks after the last dose⁶. Through P-glycoprotein, it lowers the blood thinners apixaban, dabigatran and rivaroxaban⁶.

Yes, rifampin sometimes injures the liver, and its label reports hepatitis and other patterns of liver damage. People with liver disease have liver tests before treatment and every 2 to 4 weeks during it. The label asks for close liver checks when rifampin and isoniazid are taken together¹. A 2020 NTCA and CDC guideline says the liver risk of 3HR might be greater than with either drug alone. That guideline found 4 months of rifampin caused less liver injury than 9 months of isoniazid. People finished the rifampin course more often, too. CDC guidance from 2025 lists liver injury as a serious reaction to rifampin⁵. Warning signs include belly pain, brown urine, light-colored stools, fever for 3 or more days and yellow skin or eyes⁵. The label says to stop rifampin if signs of liver damage appear or get worse¹. After liver injury, ATS, CDC and IDSA guidance from 2016 restarts the drugs one at a time, rifampin first.

These short answers cover cost, alcohol, other uses, pregnancy, rifabutin, staining, safety limits, missed doses and overdose.