With the simultaneous administration of clarithromycin with cisapride, pimozide and terfenadine in plasma, elevated concentrations of these drugs are observed, which may cause lengthening of the interval QT and heart rhythm disturbances, including ventricular tachycardia, ventricular fibrillation, arrhythmia, and torsade de pointes; Similar effects are observed with simultaneous administration of astemizole and other macrolides.
Clarithromycin does not interact with oral contraceptives.
As with other macrolide antibiotics, the simultaneous administration of clarithromycin and other drugs metabolized with the participation of cytochrome P450 (warfarin, ergot alkaloids, triazolam, midazolam, disopyramide, lovastatin, rifabutin, phenytoin, ciclosporin and tacrolimus) may be accompanied by an increase in the concentration of these drugs in the blood serum.
With the simultaneous use of clarithromycin and inhibitors HMG-KoA-reductase (lovastatin, simvastatin) it is possible to develop rhabdomyolysis.
With the simultaneous administration of clarithromycin and theophylline, the concentration of theophylline in the blood serum and its toxicity increase.
Simultaneous administration of clarithromycin and warfarin or digoxin may be accompanied by an increase in the severity of their effects.
With the simultaneous administration of clarithromycin and carbamazepine, the effect of carbamazepine may be enhanced due to a decrease in the rate of carbamazepine excretion.
With concurrent administration of clarithromycin and zidovudine (inside), HIV-infected adults may be able to reduce the equilibrium concentration of zidovudine. This can be largely avoided by increasing the interval between the use of clarithromycin and zidovudine up to 1-2 hours. For children this interaction was not noted.
With the simultaneous administration of ritonavir and clarithromycin for the latter, the values of pharmacokinetic parameters increase: the area under
the pharmacokinetic curve (AUC), the maximum concentration in the blood plasma (CmOh), the minimum concentration in the blood plasma (Cmin). For patients with normal renal function, dose adjustment is usually not required due to the wide therapeutic range of doses of clarithromycin.
With the simultaneous use of clarithromycin and omeprazole, clarithromycin and lansoprazole, as well as clarithromycin and ranitidine, an increase in the concentration of drugs in the blood plasma is possible, but usually no dose adjustment is required.
With the simultaneous use of clarithromycin and hypoglycemic agents, including insulin, in rare cases, the development of hypoglycemia is possible.