Nitroglycerin and Tadalafil: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Tadalafil
Nitroglycerin
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
Increased hypotensive effects of nitrates
Interaction Deep Dive
The concomitant use of tadalafil and organic nitrates in any form is contraindicated, either regularly or intermittently as it may result in increased risk of hypotensive effects of nitrates. Nitrates should not be used within 48 hours of the last dose of tadalafil123. Nitrates should still only be administered under close medical supervision with appropriate hemodynamic monitoring 3. Compared with placebo, significantly more patients experienced standing systolic blood pressure readings below 85 mmHg after administration of nitroglycerin 0.4 mg SL at 4, 8 and 24 hours after tadalafil 20 mg daily administration in a pharmacokinetic study (N=150); no differences in blood pressure were noted when nitroglycerin was administered at 48, 72, or 96 hours after tadalafil discontinuation 4.
Why it happens (mechanism)
Increased levels of cyclic guanosine monophosphate (cGMP) from tadalafil and nitrates
Literature reports
3 reports — tap to read
a) Compared with placebo, significantly more patients experienced standing systolic blood pressure readings below 85 mmHg after administration of nitroglycerin 0.4 mg SL at 4, 8 and 24 hours after tadalafil 20 mg daily administration in a pharmacokinetic study (N=150); no differences in blood pressure were noted when nitroglycerin was administered at 48, 72, or 96 hours after tadalafil discontinuation 4.
b) In clinical pharmacology studies, tadalafil (5 to 20 mg) was shown to potentiate the hypotensive effect of nitrates 312.
c) In a study, in some subjects who received tadalafil followed by sublingual nitroglycerin in the post– exercise period, clinically significant reductions in blood pressure were observed, consistent with the augmentation by tadalafil of the blood–pressure–lowering effects of nitrates 1.
Common questions
Can I take Nitroglycerin and Tadalafil together?
Increased hypotensive effects of nitrates Always confirm with your pharmacist or prescriber before making any change.
How serious is the Nitroglycerin and Tadalafil interaction?
It is rated contraindicated. These should generally not be used together.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
How strong is the evidence for this interaction?
The evidence is graded "established". Well documented — supported by controlled studies or strong clinical data.
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 or Tadalafil 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 a safer alternative to one of these medications for me?
References (4)
- Product Information: ADCIRCA(R) oral tablets, tadalafil oral tablets. Eli Lilly and Company (per FDA), Indianapolis, IN, 2020. DailyMed
- Product Information: OPSYNVI(R) oral tablets, macitentan tadalafil oral tablets. Actelion Pharmaceuticals US, Inc. (Per FDA), Titusville, NJ, 2024. DailyMed
- Product Information: Cialis(R) oral tablet, tadalafil oral tablet. Lilly USA, LLC (per DailyMed), Indianapolis, IN, 2023. DailyMed
- Kloner RA, Hutter AM, Emmick JT, et al: Time course of the interaction between tadalafil and nitrates. J Am Coll Cardiol 2003; 42(10):1855-1860. PubMed
Keep reading about Tadalafil
Keep reading about Nitroglycerin
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist