Erectile Dysfunction and Hypertension

R Kloner


Int J Impot Res. 2007;19(3):296-302. 

In This Article

The Nitrate Contraindication

All three PDE5 inhibitors are contraindicated in patients taking organic nitrates (including short-acting or long-acting nitroglycerin, isosorbide dinitrate, isosorbide mononitrate, amyl nitrate and others). Organic nitrates increase cyclic GMP production whereas PDE5 inhibitors decrease cyclic GMP breakdown. Therefore, there is a synergistic drop in BP when PDE5 inhibitors are given with organic nitrates that results in symptomatic hypotension in some patients.[11,12,13,15,16]

If a patient has taken a PDE5 inhibitor and then develops chest pain, when is it safe to re-introduce nitroglycerin? The original American College of Cardiology/American Heart Association guidelines suggested that for sildenafil, 5-6 half-lines or 24 h pass before nitrates are given to a patient who has taken sildenafil (half-life is about 4 h).[28] Studies comparing nitrate interaction between sildenafil versus tadalafil confirmed that there was a lack of interaction between sildenafil and nitrate 24 h after sildenafil was administered.[15] There is an unpublished study suggesting a lack of interaction with nitroglycerin at 24 h after vardenafil, consistent with its 4 h half-life.[13] Finally, one study suggests an interaction between tadalafil (half-life 17.5 h) and nitroglycerin that is present at 24 h after a dose of tadalafil but that is gone by 48 h and beyond.[29]

Thus, although all three PDE5 inhibitors are contraindicated in patients receiving either short-acting or long-acting nitrates, should a patient with ED take a PDE5 inhibitor and then develop angina, nitroglycerin should not be reintroduced until after 24 h for sildenafil or vardenafil and after 48 h for tadalafil. Of course, other antianginal and anti-ischemic therapies may be used - such as beta blockers, calcium blockers, aspirin, morphine, statins and percutaneous coronary intervention. None of these are contraindicated with PDE5 inhibitors. The American College of Cardiology/American Heart Association Guidelines address the approach to the patient who has developed hypotension in the setting of PDE5 inhibitors plus nitrates.[28]


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.