Brands, Medical Use, Clinical Data
Drug Category
- Anti-bacterial Agents
- Other Macrolides
Dosage Forms
- Oral suspension
- Capsule
- Tablet
- Powder for solution
Brands / Synonyms
Aritromicina [Spanish]; Azenil; Azithramycine; Azithromycin Dihydrate; Azithromycin Sterile; Azithromycin [Usan:Ban:Inn]; Azithromycine; Azithromycine [French]; Azithromycinum [Latin]; Azitromax; Aziwok; Aztrin; Hemomycin; Misultina; Mixoterin; Setron; Sumamed; Tobil; Tromix; Zeto; Zifin; Zithrax; Zithromax; Zitrim; Zitromax; Zitrotek
; Zmax
Indications
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
Pharmacology
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
37% (oral administration)
Toxicity
Potentially serious side effects of angioedema and cholestatic jaundice were reported
Biotrnasformation / Drug Metabolism
Hepatic. In vitro and in vivo studies to assess the metabolism of azithromycin have not been performed.
Contraindications
Zmax is contraindicated in patients with known hypersensitivity to azithromycin, erythromycin or any macrolide or
ketolide antibiotic.
Drug Interactions
Co-administration of nelfinavir at steady-state with a single dose of azithromycin (2 ´600 mg tablets) results in increased azithromycin serum concentrations. Although a dose
adjustment of azithromycin is not recommended when administered in combination with nelfinavir, close monitoring for
known side effects of azithromycin, such as liver enzyme abnormalities and hearing impairment, is warranted.
Azithromycin did not affect the prothrombin time response to a single dose of warfarin. However, prudent medical
practice dictates careful monitoring of prothrombin time in all patients treated with azithromycin and warfarin
concomitantly. Concurrent use of macrolides and warfarin in clinical practice has been associated with increased
anticoagulant effects.
Drug interaction studies were performed with azithromycin and other drugs likely to be co-administered. When used
in therapeutic doses, azithromycin had a modest effect on the pharmacokinetics of atorvastatin, carbamazepine,
cetirizine, didanosine, efavirenz, fluconazole, indinavir, midazolam, rifabutin, sildenafil, theophylline
(intravenous and oral), triazolam, trimethoprim/sulfamethoxazole or zidovudine. Co-administration with efavirenz or
fluconazole had a modest effect on the pharmacokinetics of azithromycin. No dosage adjustment of either drug is
recommended when azithromycin is co administered with any of the above agents. Interactions with the drugs listed
below have not been reported in clinical trials with azithromycin; however, no specific drug interaction studies have
been performed to evaluate potential drug-drug interaction. Nonetheless, they have been observed with macrolide
products. Until further data are developed regarding drug interactions when azithromycin and these drugs are used
concomitantly, careful monitoring of patients is advised:
Digoxinñelevated digoxin concentrations.
Ergotamine or dihydroergotamineñacute ergot toxicity characterized by severe peripheral vasospasm and
dysesthesia.
Cyclosporine, hexobarbital and phenytoin concentrations.
Laboratory Test Interactions
There are no reported laboratory test interactions.
Repeat Treatment
Studies evaluating the use of repeated courses of Zmax have not been conducted.
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