Aziro-500 Drug Interactions

Co-administration of nelfinavir at steady-state with a single oral dose of Azithromycin resulted 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.
Although, in a study of 22 healthy men, a 5-day course of Azithromycin did not affect the prothrombin time from a subsequently administered dose of warfarin, spontaneous post-marketing reports suggest that concomitant administration of Azithromycin may potentiate the effects of oral anticoagulants. Prothrombin times should be carefully monitored while the patients are receiving Azithromycin and oral anticoagulants concomitantly. Drug interaction studies were performed with Azithromycin and other drugs likely to be coadministered. When used in therapeutic doses, Azithromycin has 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 coadministered with any of the above agents. Interactions with the drugs listed as follows 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 patient is advised: Digoxin-elevated digoxin concentrations.
Ergotamine or dihydroergotamine-acute ergot toxicity characterized by severe peripheral vasospasm and dysesthesia.
Terfenadine, cyclosporine, hexobarbital and phenytoin concentrations.