Clinical Pharmacology of Rifampin in Infants and Children
Author(s): Gian Maria Pacifici
Rifampin is a macrocyclic antibiotic important in the treatment of mycobacterial diseases. This antibiotic is bacteriastatic as
inhibits the transcription of DNA to RNA by binding to the β-subunit of bacterial RNA-polymerase (rpoB) to form a stable
drug-enzyme complex. Rifampin enters bacilli in a concentration depended manner, achieving steady-state concentration within
15 min. This antibiotic inhibits the growth of most gram-positive and gram-negative microorganisms, and it is used to treat
tuberculosis, leprosy, brucellosis, Mycobacterium kansasii, mycobacterium marinum, Mycobacterium uclerans, Mycobacterium
malmoense, and Mycobacterium Haemophilus diseases. Rifampin is an effective and safe antibiotic in infants and children.
Two formulations of rifampin are available, one for oral and other one for intravenous administration. In infants, the dose of
rifampin is 10 to 20 mg/kg every 24 hours (oral administration) and 5 to 10 mg/kg every 12 hours (intravenous administration).
To treat tuberculosis rifampin is co-administered with isoniazid. The fixed dose of rifampin/isoniazid is 60/60 mg per dispersible
tablets. Concomitant administration of rifampin and isoniazid induces hepatotoxicity in children. Rifampin has been used to treat
staphylococcal, bacterial meningitis, tuberculous meningitis, and Haemophilus infections. The pharmacokinetics of rifampin has
been extensively studied in infants and children. Rifampin is extensively metabolized by different cytochromes P-450 and the
metabolites are: 25-O-desecetyrifampicin and 3-formylrifamycin SV, 25-O-desecetyrifampicin, is the mean metabolite. Rifampin
is a potent inducers of several cytochromes P-450. Rifampin, and its metabolites, are mainly excreted in the bile and eliminated
with the faeces. Little is known about the bacterial resistance to rifampin, it is approximately < 20% and is higher in younger than
older patients (P-value = 0.003). The aim of this study is to review the published data on rifampin-dosing, effects, metabolism,
pharmacokinetics, and bacterial-resistance of rifampin in infants and children.
Will be updated soon