Nitrates (cont.)

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What drugs interact with nitrates?

Nitrates can slow down metabolism of cabergoline and ergonovine, resulting in an increase in systolic blood pressure and an increased likelihood of angina symptoms.

Sildenafil (Viagra), tadalafil (Cialis) and vardenafil (Levitra) increase the blood pressure lowering effects of nitrates and may cause excessive blood pressure reduction. Patients taking nitrates should not receive sildenafil (Viagra), tadalafil (Cialis), or vardenafil (Levitra).

What formulations of nitrates are available?

Nitrates are available in various formulations. Nitroglycerin is available in:

  • oral capsule
  • sublingual tablet
  • sublingual spray
  • intravenous solution
  • topical ointment
  • topical patch
  • isosorbide mononitrate and isosorbide dinitrate are available as immediate and extended-release tablets

Only sublingual tablets, intravenous, or immediate release tablets are used for immediate treatment of angina because the onset of action of the other formulations is not fast enough.

What about taking nitrates during pregnancy or while breastfeeding?

The FDA classifies nitrates as pregnancy category C, which means that safe and effective use of nitrates in pregnant women has not been established. Nitrates should be given to pregnant women only if clearly needed.

It is not known whether nitrates enter breast milk; therefore, nitrates must be used with caution in women who are breastfeeding.

REFERENCE: FDA Prescribing Information.


Medically Reviewed by a Doctor on 11/19/2014


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