Rifampicin (also known as rifampin) is a broad-spectrum antibiotic used to treat bacterial infections such as tuberculosis (TB), leprosy, and Legionnaires’ disease.
Rifampicin (rifampin) is a cornerstone rifamycin antibiotic, primarily for tuberculosis (TB) and leprosy. Its most critical feature is potent induction of drug‑metabolizing enzymes and transporters, which causes many drug interactions.
It works by inhibiting bacterial RNA synthesis.
Rifampicin is almost always used in combination with other antibiotics to prevent the bacteria from developing drug resistance.
Primary uses include:Tuberculosis (TB): A core medication for both active and latent TB infections.
Meningitis Prevention: Used to prevent the spread of Neisseria meningitidis and Haemophilus influenzae in individuals exposed to these bacteria.
Other Infections: Treats leprosy, Mycobacterium avium complex, and severe staphylococcal infections.
Rifampicin exerts its bactericidal effects by inhibiting bacterial DNA-dependent RNA polymerase.
By blocking this enzyme, it sterically obstructs RNA synthesis, effectively halting bacterial growth and survival.
It has a distinct red-orange color which harmlessly discolors urine, sweat, tears, and saliva.
Liver Function: Because it can cause liver toxicity, doctors often recommend regular liver function tests during long-term treatments.
Drug Interactions: Rifampicin is a potent inducer of liver enzymes, meaning it accelerates the breakdown of many other drugs.
Most notably, it can reduce the effectiveness of oral contraceptives, requiring patients to use backup birth control methods.
Standard TB regimens: Typically 10 mg/kg/day (up to 600 mg), with higher doses (20–35 mg/kg) under study; doses up to 35 mg/kg for 12 weeks appeared safe in trials and may improve sterilizing activity, especially when higher peak concentration (Cmax) targets are met (≥8 µg/mL for pulmonary TB; ≥22 µg/mL for TB meningitis)
Major drug interactions (potent inducer of CYP3A4, CYP2C9, UGT, and P‑gp)
Markedly lowers levels/efficacy:HIV protease inhibitors, azole antifungals (itraconazole, ketoconazole), many calcium‑channel blockers, simvastatin, warfarin (S‑warfarin), sulfonylureas, oral contraceptives, cyclosporine, midazolam/triazolam; onset ~1 week after start, persists ~2 weeks after stop.
Opioids:Reduces methadone and other opioids, risking withdrawal; dose adjustments often needed.
Transplant meds:Can precipitate rejection (e.g., via cyclosporine; also lowers mycophenolate exposure by >50%).
High‑dose rifampicin (40 mg/kg):Adds only mild extra induction vs standard dose; existing interaction management generally still applies.