| Indication |
For the treatment of patients with mild to moderate infections
caused by susceptible strains of the designated microorganisms in the
specific conditions: H. influenzae, M. catarrhalis, S. pneumoniae, C. pneumoniae, M. pneumoniae, S. pyogenes, S. aureus, S. agal |
| Pharmacodynamics |
Azithromycin, a semisynthetic antibiotic belonging to the
macrolide subgroup of azalides, is used to treat STDs due to chlamydia
and gonorrhea, community-acquired pneumonia, pelvic inflammatory
disease, pediatric otitis media and pharyngitis, and Mycobacterium avium
complex (MAC) in patients with advanced HIV disease. Similar in
structure to erythromycin. azithromycin reaches higher intracellular
concentrations than erythromycin, increasing its efficacy and duration
of action. |
| Mechanism of action |
Azithromycin binds to the 50S subunit of the 70S bacterial
ribosomes, and therefore inhibits RNA-dependent protein synthesis in
bacterial cells. |
| Absorption |
Bioavailability is 37% following oral administration. Absorption
is not affected by food. Azithromycin is extensively distributed in
tissues with tissue concentrations reaching up to 50 times greater than
plasma concentrations. Drug becomes concentrated within macrophages and
polymorphonucleocytes giving it good activity against Chlamydia
trachomatis. |
| Volume of distribution |
|
| Protein binding |
Serum protein binding is variable in the concentration range
approximating human exposure, decreasing from 51% at 0.02 µg/mL to 7% at
2 µg/mL. |
| Metabolism |
Hepatic. In vitro and in vivo studies to assess the metabolism of azithromycin have not been performed. |
| Route of elimination |
Biliary excretion of azithromycin, predominantly as unchanged drug, is a major route of elimination. |
| Half life |
68 hours |
| Clearance |
- apparent plasma cl=630 mL/min [following single 500 mg oral and i.v. doses]
|
| Toxicity |
Potentially serious side effects of angioedema and cholestatic jaundice were reported |
