Which medicines and supplements can interact with tadalafil?

Tadalafil has several important interactions. Nitrates and recreational nitrites must not be combined with it because blood pressure can fall dangerously low. Riociguat, a medicine for certain types of high blood pressure in the lungs, must also not be combined with tadalafil.

Alpha blockers, including some medicines for prostate symptoms, and other blood pressure medicines can add to tadalafil's blood pressure effects. This does not always rule out treatment, but your prescriber may need to adjust the plan or monitor you more closely.

Some antibiotics, antifungal medicines, and HIV medicines can raise tadalafil levels in the body. Other medicines and supplements, including St. John's wort, can change how the body processes it. Grapefruit may also interact, so ask your pharmacist whether to avoid it.

Give your prescriber a complete medication list, including occasional treatments and supplements. Do not add sildenafil, another tadalafil product, or any other ED treatment on your own. Check with your prescriber or pharmacist before starting or stopping another medicine.