[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Antituberculosis drugs](https://durgical.com/en/pharmacology/classes/antituberculosis-drugs/) › Rifampicin

[Pharmacology](https://durgical.com/en/pharmacology/) · [Antituberculosis drugs](https://durgical.com/en/pharmacology/classes/antituberculosis-drugs/)

# Rifampicin

The key sterilising drug for tuberculosis and leprosy. It turns urine and tears orange-red and speeds up the breakdown of many other medicines.

Updated 2026-11-01

- Class: [Antituberculosis drugs](https://durgical.com/en/pharmacology/classes/antituberculosis-drugs/)
- Enzyme: DNA-dependent RNA polymerase, β subunit (M. tuberculosis)
- ATC code: J04AB02
- WHO Model List of Essential Medicines

Also called: Rifampin, R, RIF

✂**DNA-dependent RNA polymerase, β subunit (M. tuberculosis)**Rifampicin

ⓘ The figure shows rifampicin bound to the RNA polymerase transcription initiation complex of M. tuberculosis.

**Target in 3D:** DNA-dependent RNA polymerase, β subunit (M. tuberculosis). PDB structure 5UHB (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/5UHB) · Drag to rotate · pinch to zoom

## Mechanism of action

Rifampicin binds the β subunit of bacterial DNA-dependent RNA polymerase and blocks the growing RNA chain, so the bacillus cannot transcribe its genes; the human enzyme is not affected. It kills semi-dormant 'persister' bacilli, which is why it lets treatment be shortened. Resistance comes from mutations in rpoB, and rifampicin resistance defines RR-TB.

- Rifampicin binds the β subunit of RNA polymerase
- The new RNA chain cannot grow
- Even semi-dormant bacilli die

## Pharmacokinetics

**Absorption**
Good by mouth; food lowers absorption

**Distribution**
Wide, including cerebrospinal fluid when the meninges are inflamed

**Metabolism**
Liver deacetylation; enterohepatic circulation; it induces its own clearance

**Elimination**
Mainly bile and faeces; part in urine

**Half-life**
Short: about 2 to 3 hours with repeated dosing

## Indications

- Tuberculosis (backbone of the 6-month regimen) [Tuberculosis →](https://durgical.com/en/conditions/tuberculosis/)
- Pulmonary tuberculosis [Pulmonary tuberculosis →](https://durgical.com/en/conditions/pulmonary-tuberculosis/)
- Spinal tuberculosis (Pott disease) [Spinal tuberculosis (Pott disease) →](https://durgical.com/en/conditions/spinal-tuberculosis/)
- Leprosy, within multidrug therapy; single dose as post-exposure prophylaxis for contacts [Leprosy (Hansen disease) →](https://durgical.com/en/conditions/leprosy/)

## Adverse effects

### Common

- Harmless orange-red colour of urine, sweat, tears and sputum; stains soft contact lenses
- Nausea, abdominal discomfort
- Rash, itching
- Rise in liver enzymes

### Serious (rare, important)

- Hepatotoxicity, from enzyme rise to liver failure (more with isoniazid)
- Flu-like syndrome and other hypersensitivity reactions
- Thrombocytopenia, haemolytic anaemia, rarely disseminated intravascular coagulation
- Severe skin reactions (SJS, TEN, DRESS)
- Vitamin K-dependent bleeding

## Contraindications

- Hypersensitivity to any rifamycin
- Use with HIV protease inhibitors (atazanavir, darunavir, fosamprenavir, saquinavir, tipranavir)
- Use with cabotegravir, fostemsavir or lenacapavir
- Use with praziquantel or lurasidone

## Key interactions

**HIV protease inhibitors (darunavir, atazanavir, lopinavir/ritonavir)**
Rifampicin collapses their levels: not combined; rifabutin is used instead

**Dolutegravir and raltegravir**
Levels fall: the integrase inhibitor schedule is adjusted by the team

**Rilpivirine and doravirine**
Levels fall too much: not combined; efavirenz can be combined with rifampicin

**Hormonal contraceptives**
Lose reliability: a non-hormonal method is used

**Warfarin, methadone, oral antidiabetics, digoxin, clopidogrel**
Faster breakdown (CYP3A4 and P-glycoprotein induction): INR, withdrawal symptoms or glucose are watched

## What is monitored

- Liver enzymes, bilirubin, creatinine and blood count at baseline in adults
- Symptoms of hepatitis at every visit
- Full list of the person's medicines, including antiretrovirals
- INR if on warfarin; glucose in diabetes

## Administration and safety

- By mouth on an empty stomach; an intravenous form exists
- Often given as fixed-dose combinations with isoniazid, pyrazinamide and ethambutol
- Look-alike names: rifampicin, rifabutin, rifapentine and rifaximin are different drugs
- Daily dosing is preferred; thrombocytopenia is seen mainly with high-dose intermittent dosing

## Nursing care

- Warn that urine, sweat and tears turn orange-red and soft contact lenses can stain
- Review every medicine, especially antiretrovirals, anticoagulants, methadone and contraceptives
- Advise non-hormonal contraception during treatment
- Teach signs of hepatitis and of bleeding or bruising
- Support directly observed treatment and full adherence

## Pregnancy and breastfeeding

It crosses the placenta; when used in the last weeks of pregnancy it can cause bleeding in mother and newborn, so vitamin K may be indicated.

## Memory aid

Rifampicin's three Rs: Red fluids, Revs up the liver enzymes, RNA polymerase blocked.

## Test yourself

Think of the answer, then tap the question to see it.

## What is rifampicin's target?

The β subunit (rpoB) of bacterial DNA-dependent RNA polymerase.

## Why is rifampicin not combined with darunavir or atazanavir?

It strongly induces CYP3A4 and lowers protease inhibitor levels so much that HIV treatment would fail; rifabutin is used instead.

## A patient on TB treatment worries about orange urine. What do you explain?

It is the expected, harmless colour from rifampicin; it can also stain tears and soft contact lenses.

## What contraceptive advice goes with rifampicin?

Hormonal contraceptives become unreliable; a non-hormonal method is used.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/rifampicin/)

## Related drugs

- [Rifabutin](https://durgical.com/en/pharmacology/rifabutin/)
- [Rifapentine](https://durgical.com/en/pharmacology/rifapentine/)
- [Isoniazid](https://durgical.com/en/pharmacology/isoniazid/)
- [Dolutegravir](https://durgical.com/en/pharmacology/dolutegravir/)
- [Darunavir](https://durgical.com/en/pharmacology/darunavir/)
- [Efavirenz](https://durgical.com/en/pharmacology/efavirenz/)

## Related conditions

- [Tuberculosis](https://durgical.com/en/conditions/tuberculosis/)
- [Pulmonary tuberculosis](https://durgical.com/en/conditions/pulmonary-tuberculosis/)
- [Spinal tuberculosis (Pott disease)](https://durgical.com/en/conditions/spinal-tuberculosis/)
- [Leprosy (Hansen disease)](https://durgical.com/en/conditions/leprosy/)

[← Back to the class: Antituberculosis drugs](https://durgical.com/en/pharmacology/classes/antituberculosis-drugs/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - RIFAMPIN capsule](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b56004f0-f23d-47f6-80c7-39884fccbccc) (DailyMed (U.S. National Library of Medicine), 2025); [WHO consolidated guidelines on tuberculosis: module 4: treatment and care](https://www.who.int/publications/i/item/9789240107243) (World Health Organization (WHO), 2025); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 64 (McGraw Hill, 2023); [Leprosy](https://www.who.int/news-room/fact-sheets/detail/leprosy) (World Health Organization (WHO), 2025).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/pharmacology/rifampicin/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/rifampicin/