Rifampicin is a potent enzyme inducer and increases the metabolism of the OCP, reducing its clinical effectiveness. Alternative methods of contraception should be used. Tears and urine may turn orange. Remove soft contact lenses which can become stained.
- Useful broad spectrum bactericidal antibiotic
- Significant drug interactions as enzyme inducer
- Often used in TB therapy
Mode of action
- Binds to Beta subunit of bacterial DNA dependent RNA polymerase
- Reduced RNA synthesis and bactericidal to mycobacteria
- Liver enzyme inducer (reduced efficacy of affected drugs)
- Well absorbed and distributed
- Mycobacterial infections - TB, Leprosy
- Eradication of Meningococcal carriage
- Anti-staphylococcal activity, Endocarditis (with others)
- Legionnaire's disease, Brucellosis
- Brucellosis, anti-TB drug, endocarditis, legionella, CAP
- Rifampicin 600 mg BD PO/IV as needed
- Contraception failure and unintended pregnancy for those on OCP
- Hepatitis - Transient rise in Liver enzymes. Serious liver toxicity rare.
- Risk of liver problems more if alcohol excess or chronic liver disease
- Renal failure, Low platelets
- Red urine, sputum and tears - can discolour contact lenses
- TTP, AKI, TEN, SJS
- Rifampicin 10 mg/Kg daily before breakfast.
- Monitor LFTS, FBC, U&E before and after treatment has commenced
Reduce dose in renal failure.
- Reduce if severe renal or liver failure
- Acute Porphyria, If on Warfarin check INR
- Avoid alcohol, Reduced efficacy of Oral contraception
- Hypersensitivity, Jaundice
- Rifampicin induces hepatic enzymes increasing drug breakdown
- Reduces efficacy of OCP, Sulphonylurea, Warfarin, Steroids, Barbiturates
- Reduces efficacy of Calcium channel blockers and many other drugs
- Especially check drugs used against HIV especially Protease inhibitors
- Check BNF/Datasheet for other drugs affected