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 CCPU (RCE, Biliary, DVT, E-FAST, AAA) Rob is an Emergency Medicine Advanced Trainee based in Melbourne, Australia. He has special interests in medical education, ECG interpretation, and the use of diagnostic and procedural ultrasound in the undifferentiated and unwell patient.

Follow him on twitter: @rob_buttner | ECG Library |

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