Increases the area under the concentration-time curve (AUC) carbamazepine in patients with persistent partial epilepsy (risk of side effects such as diplopia, headache, ataxia and dizziness). Raises the AUC, the equilibrium concentration (Css) and the maximum concentration (Cmah) cyclosporine.
Increases the concentration of theophylline (due to decreased clearance), ethanol (and lengthens its effect), the concentration of quinidine (the risk of a pronounced decrease in blood pressure, especially in patients with IHSS).
It may increase the concentration of atorvastatin and lovastatin when used concomitantly.
Increases significantly AUC and Cmah simvastatin.
Raises the AUC and Cmalmotriptan, glibenclamide.
Increases the concentration of sirolimus and tacrolimus.
Increases the concentration of cardiac glycosides (requires careful monitoring and reduction of the dose of glycosides).
Raises the AUC and Cmmetoprolol and propranolol in patients with
Increases the plasma concentration of colchicine (substrate for isoenzyme CYP3A and P glycoprotein).
When ingestion significantly increases AUC and Cmah doxorubicin; IV injection of verapamil in patients with progressive neoplasms does not affect the pharmacokinetics of doxorubicin.
Slightly increases AUC imipramine; does not affect the concentration of the active metabolite, desipramine.
Increases Cmof prazosin and terazosin and AUC terazosin.
Significantly increases AUC and Cmbuspirone and midazolam.
Inhibitors CYP3A4 (incl. erythromycin, HIV protease inhibitors), telithromycin increase plasma concentrations of verapamil. Grapefruit juice increases AUC and Cmah verapamil.
Cimetidine either does not alter, or reduces the clearance of verapamil.
Rifampicin can significantly reduce bioavailability (up to 92%), and AUC and Cmah verapamil.
Rifampicin and sulfinpyrazone may reduce the antihypertensive effect of verapamil.
Phenobarbital increases the clearance of verapamil 5 times.
Sulfinpyrazone increases the clearance of verapamil by about 3 times and reduces bioavailability (60%).
Drug preparations of St. John's wort reduce AUC verapamil and, respectively, CmOh.
With simultaneous use with inhalation anesthetics, the risk of bradycardia, atrioventricular blockade, and heart failure increases.
Combination with beta-blockers can lead to an increase in the negative inotropic effect, an increased risk of developing atrioventricular conduction disorders, bradycardia (the administration of verapamil and beta-blockers should be performed at intervals of several hours).
Prazosin and other alpha-blockers, as well as other antihypertensives (angiotensin-converting enzyme inhibitors, vasodilators, diuretics, beta-blockers) increase the hypotensive effect.
Dysopyramide and flecainide should not be administered within 48 hours before or 24 hours after the use of verapamil (summation of a negative inotropic effect, up to a lethal outcome).
Increases the risk of neurotoxic effect of lithium drugs.
Strengthens the action of peripheral muscle relaxants (may require a change in the dosage regimen).
With simultaneous use with acetylsalicylic acid, there was a slightly greater increase in bleeding time than with acetylsalicylic acid alone.
Patients receiving verapamil, treatment with HMG-CoA reductase inhibitors should begin with the lowest possible doses, which later on with the continuation of the drug therapy taking into account the concentration of cholesterol in the serum.