Zhewitra 10 mg is generally a vardenafil product. It can interact with other medicines when those medicines either lower blood pressure, increase vardenafil levels, or have overlapping effects. Key interactions include: Nitrates such as nitroglycerin and isosorbide medicines: should not be combined with vardenafil because blood pressure can fall dangerously. Riociguat and other guanylate-cyclase stimulators: concurrent use is contraindicated. Alpha-blockers used for prostate or blood-pressure problems: can further Zhewitra 10 mg blood pressure, so medical supervision and dose adjustments may be needed. Certain CYP3A4 inhibitors, including ritonavir, ketoconazole, itraconazole, clarithromycin, and some HIV medicines: can increase vardenafil levels and require substantial dose restrictions or avoidance. Other ED medicines/PDE5 inhibitors: combining them with vardenafil is not recommended. Before taking Zhewitra, your doctor or pharmacist should review prescription drugs, over-the-counter medicines, and supplements you use.