Sildenafil is contraindicated in patients using long-acting nitrates or who may need to use short-acting nitrates, because the combination may cause a sharp fall of the blood pressure.
– Ned Tijdschr Geneeskd 2001 Jan 27;145(4):167-71 — Drug treatment of erection disorders in patients with cardiovascular disease — Meuleman EJ, Kingma JH.



Findings suggest that combination of sildenafil with nicorandil, as well as with nitroglycerin, potentiates the hypotensive response by augmentation of vasodilatation.
– Jpn J Pharmacol 2000 Nov;84(3):316-24 — Hypotensive interaction of sildenafil and nicorandil in rats through the cGMP pathway but not by K(ATP) channel activation. — Ishizuka N, Saito K, Akima M, Matsubara S, Saito M.



Consult with your physician before using herbs or herbal products.