Always talk to your doctor before mixing Viagra with other medications. Dangerous interactions can occur. Here’s a list of common medication categories and examples that may interact negatively with Viagra (sildenafil):
Nitrates
Nitrates, often prescribed for chest pain (angina), drastically lower blood pressure. Combining them with Viagra can cause a dangerously sharp drop in blood pressure, potentially leading to fainting, heart attack, or stroke. Examples include nitroglycerin, isosorbide mononitrate, and isosorbide dinitrate.
Alpha-blockers
These medications, used to treat high blood pressure and enlarged prostate, also lower blood pressure. The combined effect with Viagra can be significant. Common alpha-blockers include tamsulosin (Flomax), terazosin (Hytrin), and doxazosin (Cardura).
Guanylate cyclase stimulators
These medications, used to treat pulmonary hypertension, have a similar mechanism of action to Viagra. Combining them can cause excessive blood pressure lowering. An example is riociguat (Adempas).
CYP3A4 Inhibitors
These medications can increase Viagra’s levels in your blood, potentially leading to side effects. This category includes some antibiotics (like erythromycin and clarithromycin), antifungal medications (like ketoconazole and itraconazole), and HIV protease inhibitors. Your doctor needs to adjust your Viagra dosage if you are also taking a CYP3A4 inhibitor.
CYP3A4 Inducers
These medications can decrease Viagra’s levels in your blood, reducing its effectiveness. Examples include rifampin (used to treat tuberculosis) and St. John’s Wort (a herbal supplement).
This list isn’t exhaustive. Many other medications can interact with Viagra. Always provide your doctor with a complete list of all your medications, supplements, and herbal remedies before starting Viagra or any other new medication.
