What the FDA labels say about taking them together
Isosorbide dinitrate and sildenafil
Isosorbide dinitrate's FDA label of March 2, 2020 names sildenafil in its contraindications section; sildenafil's label does not name isosorbide dinitrate itself but warns about its class (nitrate vasodilators). The isosorbide dinitrate label: “Do not use Isosorbide Dinitrate in patients who are taking certain drugs for erectile dysfunction, such as sildenafil, tadalafil, or vardenafil.”
Check it at the source: the isosorbide dinitrate FDA label on DailyMed (effective March 2, 2020, Oceanside Pharmaceuticals); the sildenafil FDA label on DailyMed (effective November 17, 2023, Viatris Specialty LLC).
What does the isosorbide dinitrate label say about sildenafil?
Isosorbide dinitrate label, contraindicationsDo not use Isosorbide Dinitrate in patients who are taking certain drugs for erectile dysfunction (phosphodiesterase inhibitors), such as sildenafil, tadalafil, or vardenafil.
Isosorbide dinitrate label, warningsWARNINGS Amplification of the vasodilatory effects of Isosorbide Dinitrate by sildenafil can result in severe hypotension.
Source: FDA drug label (Isosorbide Dinitrate), NDA012093 (Bausch), as published by Oceanside Pharmaceuticals, effective March 2, 2020 (SPL set 723d9f78-9d77-4575-af27-1aa117e6b8d7), via openFDA; the full label on DailyMed
What does the sildenafil label say about isosorbide dinitrate?
Sildenafil's label does not name isosorbide dinitrate itself; it warns about its class (nitrate vasodilators):
Sildenafil label, contraindicationsCONTRAINDICATIONS Administration of VIAGRA to patients using nitric oxide donors, such as organic nitrates or organic nitrites in any form.
Sildenafil label, contraindicationsConsistent with its known effects on the nitric oxide/cGMP pathway [ see Clinical Pharmacology (12.1 , 12.2) ], VIAGRA was shown to potentiate 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.
Source: FDA drug label (Viagra), Viatris Specialty LLC, effective November 17, 2023 (SPL set d905dc8d-917f-4ea3-a4ee-a1ecf6967d4e), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Isosorbide dinitrate | Sildenafil | |
|---|---|---|
| Labeled for | Angina | Erectile dysfunction, Pulmonary arterial hypertension |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.154 per tablet 10 mg tablet | $0.132 per tablet 100 mg tablet |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once