Pharm 101: Rifampicin

Class

Antibiotic

Pharmacodynamics
  • Inhibits bacterial RNA synthesis
  • Bactericidal for mycobacteria
Pharmacokinetics
  • Well absorbed orally
  • Highly lipid soluble, widely distributed
  • High plasma protein binding
  • Hepatic metabolism:
    • Biliary excretion
    • Undergoes enterohepatic recirculation
    • Half-life 3.5 hours
  • CYP enzyme inducer
Antimicrobial activity
  • Gram positive organisms
  • Some gram-negative organisms, including Neisseria, Haemophilus, mycobacteria, and chlamydiae
  • Clinical uses:
    • Mycobacterial infections (first line for TB, combination with isoniazid or other antituberculosis drugs)
    • Eliminates meningococcal carriage
    • Prophylaxis following H influenzae exposure
    • Serious Staph infections e.g. endocarditis
Adverse effects
  • Orange discolouration of body fluids
  • Rash
  • Cholestatic jaundice and hepatitis
  • Flu-like syndrome with intermittent dosing (if given less than twice per week)
  • CYP enzyme inducer
Precautions/contraindications
  • Resistance commonly emergences when used as single drug in treatment of active TB
  • No dose adjustment required in hepatic or renal insufficiency
References
Pharm 101 700

Pharmacology 101

Top 200 drugs

MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner

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