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Antituberculous Agents

Rifampicin

Brand names: Rifadin, Rimactane

Rifampicin is a first-line rifamycin antibiotic used throughout treatment of active tuberculosis and for some other serious infections and prophylaxis, given orally or intravenously. In respiratory practice it forms a core component of combination TB therapy.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It inhibits bacterial DNA-dependent RNA polymerase, suppressing RNA synthesis and exerting a bactericidal effect on susceptible mycobacteria and bacteria.

Prescribing in practice

  • Rifampicin is a potent inducer of hepatic cytochrome P450 enzymes and reduces the effect of many drugs, including hormonal contraceptives, so review all medicines and advise additional contraception.
  • It commonly causes orange-red discolouration of urine, tears and other body fluids and can stain soft contact lenses; warn patients this is harmless.
  • Monitor liver function and use within a multidrug TB regimen to prevent resistance.

Monitoring

Monitor liver function and full blood count, and review for drug interactions and hepatotoxicity throughout treatment.

Counselling the patient

  • Your urine, tears and sweat may turn orange-red, which is harmless but can stain contact lenses.
  • Use extra contraception, as rifampicin can stop the pill working.
  • Take it as prescribed with your other TB medicines and report yellowing of the skin or eyes.

Evidence & guidelines

Established UK tuberculosis guidance positions rifampicin as a core agent throughout combination treatment of active disease.

Reference: NICE NG33 (TB 2016); WHO TB Guidelines 2022; MHRA SPC Rifadin; BTS TB Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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