Nitroglycerin Spray and Nitric Oxide: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Nitroglycerin Spray
Nitric Oxide
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
An increased risk of methemoglobinemia
Interaction Deep Dive
Nitroglycerin is a nitric oxide donor and may have an additive effect on nitric oxide-induced methemoglobinemia. Concurrent administration of nitric oxide inhalation with nitroglycerin may result in an increased risk for methemoglobinemia1. Caution is advised, and patients should be monitored for symptoms of methemoglobinemia when nitric oxide and nitroglycerin are coadministered.
Why it happens (mechanism)
Additive effect on nitric oxide-induced methemoglobinemia
Common questions
Can I take Nitroglycerin Spray and Nitric Oxide together?
An increased risk of methemoglobinemia Always confirm with your pharmacist or prescriber before making any change.
How serious is the Nitroglycerin Spray and Nitric Oxide interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Nitroglycerin Spray or Nitric Oxide need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (1)
- Product Information: INOMAX(R) inhalation, nitric oxide inhalation. INO Therapeutics, Clinton, NJ, 2009. DailyMed
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