See also How to Use section.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug are: riociguat, vericiguat.

Vardenafil can cause a serious drop in your blood pressure when used with nitrates, which can lead to dizziness, fainting, and rarely heart attack or stroke. Do not use vardenafil with any of the following: certain drugs used to treat chest pain/angina (nitrates such as nitroglycerin, isosorbide), recreational drugs called "poppers" containing amyl or butyl nitrite.

If you are also taking an alpha blocker medication (such as doxazosin, tamsulosin) to treat an enlarged prostate/BPH or high blood pressure, your blood pressure may get too low which can lead to dizziness or fainting. Your doctor may start treatment with a lower dose of vardenafil to minimize your risk of low blood pressure.

Other medications can affect the removal of vardenafil from your body, which may affect how vardenafil works. Examples include azole antifungals (such as itraconazole, ketoconazole), macrolide antibiotics (such as clarithromycin, erythromycin), HIV protease inhibitors (such as indinavir), ritonavir, among others.

Do not take this medication with any other product that contains vardenafil or other similar medications used to treat erectile dysfunction-ED or pulmonary hypertension (such as sildenafil, tadalafil).