With caution, it is necessary to take azithromycin in case of simultaneous use of other drugs that can prolong the QT-interval.
During the study of the drug-antacid interaction, there was no change in the level of bioavailability, although peak plasma levels were reduced by about 25%. Therefore, it is recommended to use azithromycin before taking antacid drugs (for 1 hour) or after it (after 2 hours).
Derivatives of ergot in combination with azithromycin in theory can provoke the emergence of ergotism.
Some representatives of related macrolides affect the metabolism of cyclosporine. Since clinical and pharmacokinetic tests for possible interaction in the case of concomitant reception of Azimed with cyclosporine have not been performed, it is necessary to carefully evaluate the clinical picture before the appointment of a complex reception of drug data. If combined therapy is considered justified, during the course it will be necessary to carefully monitor the parameters of cyclosporine and adjust the dose according to them.
Azithromycin does not affect the anticoagulant properties of a single dose (15 mg) of warfarin, although there is evidence of an increase in these properties with the simultaneous use of coumarinic anticoagulants (orally) with azithromycin. It was not possible to identify the cause of such an impact, but it is necessary to take this fact into account. Therefore, it is recommended to constantly monitor the rate of PTV in individuals treated with these drugs.
In some treated individual macrolides may affect the process of intestinal metabolism of digoxin. Therefore, when a combination of azithromycin with this drug is required to remember the possible increase in digoxin indicators and monitor their changes during the treatment period.
There is no information on the interaction of azithromycin and terfenadine. Simultaneous reception of these drugs should be done with caution.
Combination with theophylline does not lead to a change in the pharmacokinetic characteristics of this substance. However, the combined use of theophylline with other macrolides in certain cases may cause an increase in its serum levels.
One-time use of 1000 mg of zidovudine in combination with repeated administration of azithromycin in doses of 600 or 1200 mg does not lead to a change in the plasma pharmacokinetics of zidovudine, as well as its (together with glucuronide degradation products) urinary excretion. However, azithromycin increases the phosphorylated zidovudine (a drug-active degradation product inside mononuclear cells in the peripheral blood stream).
Combined use of the drug with rifabutin does not affect their plasma performance. As a result of this combination, neutropenia may develop (although in this case, the reason is most likely the reception of rifabutin, because it was not possible to connect the development of this disorder with the use of this substance in combination with azithromycin).
As a result of taking nelfinavir, the serum level of azithromycin rises. Correct the dosage of the drug when combined with nelfinavir is not needed, but it is required to monitor the patient's condition for the occurrence of side effects of azithromycin.