Rifamycin Antibiotic

Rifampicin

Brand names: Rimactane, Rifadin

Rifampicin is an antibiotic central to tuberculosis treatment and used for some other serious infections (e.g. as part of combination therapy in prosthetic-related or staphylococcal infection) and for meningococcal prophylaxis.

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.

US labelling (FDA)

Reference — US labelling, may differ from UK

DOSAGE AND ADMINISTRATION Rifampin can be administered by the oral route or by IV infusion (see INDICATIONS AND USAGE ). IV doses are the same as those for oral. See CLINICAL PHARMACOLOGY for dosing information in patients with renal failure. Tuberculosis Adults: 10 mg/kg, in a single daily administration, not to exceed 600 mg/day, oral or IV Pediatric Patients: 10–20 mg/kg, not to exceed 600 mg/day, oral or IV It is recommended that oral rifampin be administered once daily, either 1 hour before or 2 hours after a meal with a full glass of water. Rifampin is indicated in the treatment of all forms of tuberculosis. A three-drug regimen consisting of rifampin, isoniazid, and pyrazinamide is …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2026-05-27. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

It inhibits bacterial DNA-dependent RNA polymerase, blocking transcription.

Prescribing in practice

It is a potent enzyme inducer with many interactions — it reduces the effectiveness of hormonal contraception, warfarin, many antiretrovirals and others; counsel and adjust accordingly.
It must be used in combination (never alone) for active TB to prevent resistance; hepatotoxicity occurs (monitor).
It colours urine, tears, sweat and other secretions orange-red (harmless, but stains soft contact lenses); intermittent dosing can cause a flu-like reaction.

Monitoring

Monitor liver function (and full blood count); review all co-medications for interactions.

Counselling the patient

Your urine, tears and sweat may turn orange-red — this is harmless but can stain contact lenses.
It makes the contraceptive pill and some other medicines less effective — use additional contraception and tell your clinician about all your medicines.
Report yellowing of the skin or eyes, or feeling unwell.

Evidence & guidelines

A cornerstone of TB therapy (always in combination) and used for selected other infections and prophylaxis (NICE NG33).

Reference: NICE NG33 TB; British Thoracic Society 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).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways