Rifampicin

Rifampicin is active against a wide range of Gram +ve and Gram -ve organisms, but resistance readily emerges during therapy due to preexisting mutants present in most bacterial populations. It must therefore be used with a second antibiotic active against the target pathogen. Its major use is for therapy of tuberculosis.

Uses
In combination with vancomycin for:
• penicillin-resistant pneumococcal infections including meningitis
• serious Gram + ve infections including those caused by MRSA
• prosthetic device-associated infections

Legionnaires’ disease (in combination with a macrolide antibiotic) Prophylaxis of meningococcal meningitis and Haemophilus influenza (type B) infection Combination therapy for infections due to Mycobacterium tuberculosis

Contraindications
Porphyria
Jaundice

Administration
• Serious Gram +ve infections (in combination with vancomycin)
• Legionnaires’ disease (in combination with a macrolide antibiotic)
  Oral or IV: 600 mg 12 hourly
• Prophylaxis of meningococcal meningitis infection
  Oral or IV: 600 mg 12 hourly for 2 days
  Child 10 mg/kg (under 1 year, 5 mg/kg) 12 hourly for 2 days
• Prophylaxis of Haemophilus influenzae (type b) infection
  Oral or IV: 600 mg once daily for 4 days
  Child 1–3 months 10 mg/kg once daily for 4 days, over 3 months
  20 mg/kg once daily for 4 days (maximum 600 mg daily)

IV formulations are available as Rifadin and Rimactane Reconstitute with the solvent provided, then dilute with 500 ml (for Rifadin) or 250 ml (for Rimactane) of glucose 5%, sodium chloride 0.9% or Hartmann’s solution, given over 2–3 hours
Monitor: FBC, U&E, LFT

Adverse effects
GI symptoms (nausea, vomiting, diarrhoea)
Bodily secretions (urine, saliva) coloured orange-red
Abnormal LFT
Haemolytic anaemia
Thrombocytopenic purpura
Renal failure

Cautions
Discolours soft contact lenses
Women on oral contraceptive pills will need other means of contraception

Organ failure
Hepatic: avoid or do not exceed 8 mg/kg daily (impaired elimination)