Aluminium/magnesium hydroxide antacids: May reduce the peak levels of azithromycin, and administration should be separated.
Anticoagulants: A marked increase in the effects of warfarin and bleeding has been seen in a small number of patients given azithromycin, but most patients are unlikely to develop a clinically important interaction.
Digitalis glycosides: Some patients unpredictably show a rapid and marked two to fourfold increase in serum digoxin levels when given azithromycin. The same interaction has been seen with digitoxin and azithromycin. Digitalis toxicity can occur.
Ergotamine or dihydroergotamine: Acute ergot toxicity characterized by severe peripheral vasospasm and dysesthesia.
Triazolam: Decreases the clearance of triazolam and thus may increase the pharmacologic effect of triazolam.
Drugs metabolized by the cytochrome P-450 system: Elevations of serum carbamazepine, cyclosporine, hexobarbital, and phenytoin levels.