It is required to combine with caution the azithromycin with other drugs that can prolong the QT-interval (such are ketoconazole with lithium, and in addition quinidine together with terfenadine, as well as cyclophosphamide with the substance haloperidol).
In the process of studying drug interaction with antacids, there was no change in the bioavailability of azithromycin, although the peak level of the substance inside the plasma decreased by 25%. It is required to use azithromycin at least 1 hour before using antacids or 2 hours after.
Combined drug administration with cetirizine (20 mg dose) during 5 days did not cause pharmacokinetic interaction at equilibrium indices, but significantly changed the QT-interval values.
The combination of Azitra with ergot alkaloids or dihydroergotamine can provoke the development of vasoconstrictive action accompanied by perfusion disorders, which results in the defeat of the fingers on the legs and hands. Because of this, it is necessary to avoid such combinations.
In the case of using cimetidine 2 hours before taking azithromycin, the pharmacokinetic parameters of the latter were not found to change.
Individual macrolides are able to affect the metabolism of cyclosporine. Because of this, with the combined use of these funds, it is required to constantly monitor the cyclosporine parameters and to change the applied dose in accordance with them.
Combination of the drug with warfarin may increase the anticoagulant effect, and therefore it is necessary to monitor the indices of PTV during the treatment period.
There is information that macrolides are capable of affecting the intestinal metabolism of digoxin, so that combined use of these medicines requires regular monitoring of digoxin values.
The drug does not affect the pharmacokinetic parameters of theophylline in the case of their combined use. But in this case, the simultaneous administration of theophylline with other macrolides caused an increase in the serum indices of this substance.
The administration of zidovudine once in the amount of 1000 mg in combination with azithromycin (repeated use of 600 or 1200 mg doses) did not affect the pharmacokinetic parameters, as well as the excretion of urinary zidovudine or its glucuronic degradation products. But the use of azithromycin led to an increase in the level of zidovudine phosphorylated type within mononuclear cells in the peripheral blood flow system.
The combined Azithra with rifabutin had no effect on the values of these drugs inside the plasma. People who used these drugs at the same time developed neutropenia, but it should be taken into account that it was not possible to connect the occurrence of this disorder with the use of azithromycin.
Admission together with cisapride is able to prolong the prolongation of the QT-interval, and in addition to increase the arrhythmia of the ventricles or the syndrome of fibrillation. Because of this, it is recommended not to combine these substances.
Combined use with alfentanil or astemizole should be done with caution, because in combination with erythromycin, there was an increase in exposure.
With simultaneous reception with nelfinavir, the equilibrium serum azithromycin values increase. Although it is not recommended to change the dosage of the drug in the case of a combination with nelfinavir, careful monitoring of the development of the negative effects of azithromycin will be justified.
It is required to bear in mind the possibility of developing cross-resistance between azithromycin, as well as other macrolides (eg erythromycin) and clindamycin with lincomycin.