First-line Tuberculosis Drug

Rifampicin

A rifamycin antibiotic at the core of tuberculosis treatment, also used for leprosy and to clear meningococci from carriers.

Also called rifampin (US name) or R (letter in TB regimen codes).

Drug card

Class: First-line tuberculosis drug
How it works: Blocking bacterial RNA polymerase, so the bacterium cannot make RNA
Used for: Active tuberculosis, with other TB drugs
Latent TB infection, alone or with isoniazid
Leprosy, in multidrug therapy
Clearing meningococci from healthy carriers
Known for: Orange-red urine, sweat, tears and saliva
Hepatitis, rarely liver failure
Its name: rifa- means a rifamycin antibiotic

Study it as a flashcard, and it comes back before you forget it.

Mechanism of action

How does rifampicin work?

Binds bacterial DNA-dependent RNA polymerase, which the human enzyme escapes, and stops transcription. Resistance emerges quickly if it is used alone. It strongly induces liver enzymes (CYP3A4 and others), glucuronidation and P-glycoprotein, so it speeds the clearance of many other drugs.

Like other first-line tuberculosis drugs: The four first-line drugs hit Mycobacterium tuberculosis in different ways: isoniazid and ethambutol stop it building its cell wall (mycolic acids and arabinogalactan), rifampicin blocks its RNA polymerase, and pyrazinamide acts on slowly dividing bacilli at acidic pH. Resistance arises fast to any one drug alone, so they are given together: all four for 2 months, then isoniazid and rifampicin for 4.

Uses

What is rifampicin used for?

Active tuberculosis, with other TB drugs
Latent TB infection, alone or with isoniazid
Leprosy, in multidrug therapy
Clearing meningococci from healthy carriers

Side effects

Side effects of rifampicin

Orange-red urine, sweat, tears and salivaKnown for
Hepatitis, rarely liver failureKnown forSerious
Flu-like syndrome
Itching and flushing
Low platelets and bleedingSerious
TTP/HUS (thrombotic microangiopathy)Serious
Severe skin reactions: SJS, TEN, DRESSSerious
Kidney injurySerious
Hemolytic anemiaSerious
Interstitial lung diseaseSerious
Tooth discoloration
C. difficile diarrheaSerious

Known for marks what an exam expects you to know it for.

Watch for

Cautions and what sets it apart

Strong enzyme inducer: it lowers levels of warfarin, many HIV drugs, azole antifungals and more, so check every co-prescribed drug.
Contraindicated with several HIV protease inhibitors (such as atazanavir and darunavir), praziquantel and lurasidone.
Hormonal contraception may fail, so another method is advised.
Watch liver function, especially in liver disease or with other liver-toxic drugs such as isoniazid.

Good to know: Rifampicin is the INN; rifampin is the US name. Its color stains urine, sweat, sputum, tears and soft contact lenses.

Remember it

A way to remember it

RIPE

R: Rifampicin: orange-red urine, sweat and tears
I: Isoniazid: peripheral neuropathy and hepatitis
P: Pyrazinamide: high uric acid and gout
E: Ethambutol: eye damage (optic neuritis)

RIPE names the four first-line drugs, and each letter carries the side effect that drug is best known for.

A mnemonic widely used in teaching

Its name

rifa- means rifamycin antibiotic
Rifampicin (US name rifampin), rifabutin, rifapentine and rifaximin share it. Rifampicin is a first-line tuberculosis drug.
Every drug name stem

Its class

First-line tuberculosis drugs

Other first-line tuberculosis drugs with a card:

Easily mixed up with fluoroquinolones.

All about first-line tuberculosis drugs

Sources

Checked against

Written for biofideX in plain words, after checking these references:

For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.

Practice it

Antibiotics: DNA, folate and tuberculosis

Rifampicin is one of 11 drugs practiced together here: their classes, how they work, what they treat and what they're known for.

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