[Clinical pharmacokinetics of azithromycin].
The bioavailability of azithromycin is approximately 37%. Concomitant administration of oral azithromycin with food significantly decreases by 50% drug bioavailability. Following a single oral 500 mg dose, peak plasma concentrations of about 0.35-0.45 mg/l are attained within approximately 2 hours. With a 500 mg oral dose on day 1, followed by 250 mg daily on days 2 to 5, peak and through plasma concentrations on day 5 are around 0.25 and 0.05 mg/l respectively. These low plasma concentrations are the consequence of extensive and rapid distribution from plasma to tissues. Plasma protein binding is low, less than 50% at plasma concentrations obtained with the usual dosage regimen. Apparent volume of distribution is very large, 25 to 35 l/kg. Azithromycin is mainly eliminated unchanged in the faeces via biliary excretion and transintestinal secretion. Urinary excretion is a minor elimination route: about 6% and an oral dose and 12% of an intravenous dose are recovered unchanged in urine. The mean terminal elimination half-life of azithromycin is 2 to 4 days. The pharmacokinetics of azithromycin is not significantly altered in elderly subjects and in patients with mild to moderate renal or hepatic insufficiency.
Pharmacie Clinique, Groupe Hospitalier Necker Enfants-Malades, Paris, France.
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Singlas
D000284:Administration, Oral; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics; D017963:Azithromycin / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*; D006801:Humans; D007262:Infusions, Intravenous; D017093:Liver Failure / Q000097:blood* / Q000652:urine; D012016:Reference Values; D051437:Renal Insufficiency / Q000097:blood* / Q000652:urine
D000900:Anti-Bacterial Agents; D017963:Azithromycin
Pharmacocinétique clinique de l'azithromycine.