Azithromycin is used with caution in combination with other drugs that can prolong the QT-interval.
During the study of the effect of antacid drugs on the pharmacokinetic properties of azithromycin, their combined administration did not generally change the bioavailability, but a decrease in the peak plasma values of azithromycin (by 30%) was observed. As a result, it is required to use azithromycin at least 1 hour before taking antacid medicines or 2 hours afterwards.
Certain related macrolides affect the metabolic processes of the substance cyclosporin. Since clinical and pharmacokinetic tests for possible interaction with combined use of azithromycin with cyclosporine have not been performed, the clinical picture before the appointment of combined therapy using these agents must be carefully evaluated. If the doctor found this combination to be justified, careful regular monitoring of the cyclosporine values would be necessary in order to adjust its dose as necessary.
There is evidence of increased rates of bleeding in the case of concomitant medication with warfarin or oral anticoagulants coumarinovogo number. Because of this, while simultaneously receiving such drugs it is required to constantly monitor the level of the PTV.
In some patients, the development of the effect of certain macrolides on intestinal metabolism of digoxin has been observed. Therefore, when digoxin is combined with Azith, it is required to constantly monitor digoxin digestion in the body, since its level may increase.
Azithromycin had no effect on the pharmacokinetic properties of theophylline in the case of concomitant use of these drugs by volunteers. In the period of simultaneous administration of theophylline with other macrolides, the serum values of this substance sometimes increased.
The combination of zidovudine (a single dose of 1000 mg) with azithromycin (a reusable dose of 600 or 1200 mg) did not lead to a change in the pharmacokinetics of zidovudine within the plasma, and in addition excretion of this substance or its glucuronic degradation products along with urine. But the use of azithromycin led to an increase in the level of phosphorylated zidovudine (a drug-active product of disintegration inside peripheral blood mononuclear cells). The medicinal value of this information is not known.
The combined use of daily doses of azithromycin (1200 mg) with didanosine in 6 people did not lead to a change in the pharmacokinetic characteristics of the latter (in comparison with placebo).
The combined use of the drug with rifabutin had no effect on the indices of these drugs inside the plasma. Some patients sometimes develop neutropenia, but its appearance is associated with the use of rifabutin, and the association with the combined use of azithromycin has not been established.