Rifampin

Background

• Inhibits bacterial DNA-dependent RNA polymerase
• Never given alone due to rapid resistance

Dosing

• As adjunct to fluoroquinolone for Staphylococcus aureus:
  • Weight <60 kg: 600 mg p.o. daily
  • Weight >60 kg: 450 mg p.o. twice daily

Safety

• Avoid in liver failure

Adverse Effects

• Orange or red discoloration of body fluids
• Drug-drug interactions, rash, hepatitis, influenza-like illness, neutropenia, and thrombocytopenia
• Drug-drug interactions
• Flu-like syndrome, a type III hypersensitivity reaction characterized by fevers, chills, myalgias, and arthalgias usually 1-4 hours (but up to 12 hours) after a dose, and lasts for 8 hours; if rechallenged, can develop hypotension and shock

Drug-Drug Interactions

• Multiple
• Induces CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A
• Other antibiotics include clindamycin, doxycycline, linezolid, moxifloxacin, trimethoprim, and fusidic acid