Q. Apart from nitrate-based drugs, which medications interact adversely with Viagra? If I’m taking one of those drugs that make it difficult for Viagra to do its job, what alternatives do I have?
A. As with nitrates, there are a handful of other drugs that are totally incompatible with Viagra because taken together they lower blood pressure sharply and could cause extreme dizziness, fainting, and possible loss of consciousness. These drugs would include other PDE5 inhibitors, such as Cialis, Levitra, Staxyn, and Stendra, as well as riociguat, which is sold under the brand name Adempas and is prescribed to treat two different forms of pulmonary hypertension.
Still, other types of drugs that can interact adversely with Viagra include certain antibiotics, such as clarithromycin (Biaxin) and erythromycin (EryPed), and antifungals, such as fluconazole (Diflucan) and itraconazole (Sporanox). Also known to interact poorly with Viagra are some heart and blood pressure medications, such as amlodipine (Norvasc) and amiodarone (Cordarone, Nexterone, Pacerone), and the tuberculosis drug isoniazid.
Adverse interactions have also been recorded between Viagra and cimetidine (Tagamet), bosentan (Tracleer), imatinib (Gleevec), nefazodone (Serzone), St. John’s wort, boceprevir (Victrelis), ritonavir (Norvir), amprenavir (Agenerase), and atazanavir (Reyataz).
If you are taking one of these medications, you can check with your doctor to see if he can switch you to an alternative drug that doesn’t interact adversely with Viagra. Absent that, it probably bests that you stay away from Viagra or any other PDE5 inhibitor until your primary health issue is resolved.