* Sildenafil (Viagra). Concomitant administration of<unk>  and sildenafil (Viagra) or other phosphodiesterase inhibitors (Tadalafil and Udenafil) can potentiate the vasodilatory effect of<unk>  with the potential result of serious side-effects such as syncope or myocardial infarction. Life-threatening hypotension may also occur. Therefore, sildenafil should not be given to patients already receiving<unk>  therapy. * Sulfhydryl-containing compounds. The metabolism of organic nitrates to nitric oxide is dependent on the presence of sulfhydryl groups in the muscle. The combination of oral N-acetylcysteine and a single dose of sustained-release<unk>  60 mg significantly prolonged the total exercise time in patients with angina pectoris and angiographically proven significant coronary artery disease, when compared with<unk>  alone. Concomitant administration of other exogenous sources of sulfhydryl groups such as methionine and captopril may produce a similar interaction. * Phenylalkylamine calcium antagonists. The addition of a calcium channel blocker of the verapamil type, such as gallopamil 75 mg, has been shown to further improve left ventricular functional parameters when given in combination with<unk>  in a sustained-release formulation. * Propranolol. The addition of<unk>  to propranolol treatment in patients with cirrhosis and portal hypertension caused a marked fall in portal pressure, a reduction in hepatic blood flow, cardiac output and mean arterial blood pressure, but no additional change in azygos blood flow. The additional effect of<unk>  was especially evident in patients whose portal pressure was not reduced by propranolol. * Calcium antagonists (general). Marked symptomatic orthostatic hypotension has been reported when calcium antagonists and organic nitrates were used in combination. Dose adjustments of either class of agent may be necessary.
Isosorbide mononitrate
Isosorbide dinitrate
Sodium nitroprusside
Minoxidil
Balsalazide
Hydralazine
Telmisartan
Captopril