Nitroglycerin and Sildenafil interaction
Nitroglycerin and Sildenafil: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Nitroglycerin (NITROGLYCERIN LINGUAL) label · effective 2025-12-17
Use of phosphodiesterase type 5 (PDE-5) Inhibitors, such as avanafil, sildenafil, tadalafil, or vardenafil, or soluble guanylate cyclase (sGC) stimulator (riociguat).
P DE-5 - I nhibitors and sGC- S timulators Do not use Nitroglycerin Lingual Spray in patients who are taking PDE-5-Inhibitors, such as avanafil, sildenafil, tadalafil, or vardenafil.
PDE-5-Inhibitors such as avanafil, sildenafil, vardenafil, and tadalafil have been shown to potentiate the hypotensive effects of organic nitrates.
From the Sildenafil label · effective 2026-07-17
CONTRAINDICATIONS Administration of SILDENAFIL ORAL FILM to patients using nitric oxide donors, such as organic nitrates or organic nitrites in any form.
SILDENAFIL ORAL FILM was shown to potentiate the hypotensive effect of nitrates.
…its known effects on the nitric oxide/cGMP pathway [see Clinical Pharmacology ( 12.1 , 12.2 ) ] , SILDENAFIL ORAL FILM potentiates the hypotensive effects of nitrates, and its administration to patients who are using nitric oxide donors such as organic nitrates or organic nitrites in any form either regularly and/or intermittently is therefore contraindicated.
After patients have taken SILDENAFIL ORAL FILM it is unknown when nitrates, if necessary, can be safely administered.
Although plasma levels of sildenafil at 24 hours post dose are much lower than at peak concentration, it is unknown whether nitrates can be safely co-administered at this time point [see Dosage and Administration ( 2.2 ), Drug Interactions ( 7.1 ), and Clinical Pharmacology ( 12.2 ) ].
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.