Sildenafil and Nitrates: Can You Take Them Together?

Glyceryl trinitrate and Sildenafil interaction
, reviewed by​
Kim Matthews
 – Updated October 17, 2022
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The instructions for taking Sildenafil contain a warning about the inadmissibility of its combination with nitrates. Why?

Taking both Sildenafil and nitrates leads to the expansion of blood vessels. Accordingly, this effect can increase significantly if you take these drugs simultaneously or close in time to each other. The result can be a sharp drop in blood pressure and an increased risk of heart attack or ischemic stroke.

The recommendations of the Committee on Safety of Medicines say that:
You cannot take Sildenafil and nitrates used for cardiovascular diseases, such as GTN spray and the recreational drug amyl nitrate, at the same time;

People with severe heart failure or unstable angina should not use Sildenafil.

The British Heart Foundation confirmed these recommendations, stating that nitrate therapy is absolutely incompatible with PDE-5 inhibitors such as Sildenafil, Tadalafil and Verdenafil.

Doctors strongly advise against taking Sildenafil within 24 hours of taking medicines containing nitrates. In addition to lowering blood pressure, combining these two drugs can cause dizziness, fainting, or other serious effects.

Nitroglycerin and Sildenafil

There were no human trials on the simultaneous use of Sildenafil and nitroglycerin. A scientific paper published in 2000 noted that the combination of Sildenafil and nitrates may have caused the death of 16 people, but a direct link has not been definitely proven.

It also mentions several small studies where men taking Sildenafil received nitroglycerin or isosorbide mononitrate. They had a sudden and severe decrease in blood pressure.

“Sildenafil citrate is contraindicated for people who are prescribed (or may suddenly need) organic nitrates such as sublingual tablets or nitroglycerin patches,” the scientists concluded.

Glyceryl trinitrate and Sildenafil interaction

There must be an interval of at least 4 hours between taking glyceryl trinitrate (GTN) and Sildenafil citrate.

American Journal of Hypertension says it.

You should not use this spray if you:

  • Had a stroke;
  • Have any heart problems other than angina;
  • Have hypotension.


Sildenafil and nitrates have the same effect on the body, dilating blood vessels and accelerating blood flow. While these drugs alone produce a predictable positive result, when taken together, they can create a cumulative effect that can lead to a sudden and significant drop in blood pressure. It can also cause other complications such as fainting, etc.

So, the simultaneous use of nitrates (including nitroglycerin and GTN spray) and Sildenafil citrate is prohibited. There must be an interval of at least 24 hours between taking these medicines.

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