Does Nitroglycerin Interact with Labetalol?
Nitroglycerin and Labetalol have a moderate drug interaction according to U.S. FDA drug labeling data. Labetalol blunts reflex tachycardia from nitroglycerin and may produce additional antihypertensive effects when used concomitantly in angina patients. The mechanism involves blunting of reflex tachycardia combined with additive hypotensive effects. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This information is based on official FDA drug labeling sourced from OpenFDA and the NIH National Library of Medicine.
- Severity
- Moderate
- Nitroglycerin Class
- Nitrate Vasodilator
- Labetalol Class
- beta-Adrenergic Blocker
- Management
- Monitor for effects
- Data Source
- U.S. FDA via OpenFDA
How This Interaction Works
The interaction between Nitroglycerin and Labetalol occurs because blunting of reflex tachycardia combined with additive hypotensive effects. Clinically, this means labetalol blunts reflex tachycardia from nitroglycerin and may produce additional antihypertensive effects when used concomitantly in angina patients. This is classified as a moderate interaction. While it may not require stopping either medication, your healthcare provider should be aware you are taking both so they can monitor for potential effects and adjust treatment if necessary.
What To Tell Your Doctor or Pharmacist
If you are taking Nitroglycerin and your doctor is considering prescribing Labetalol (or vice versa), make sure to:
- Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
- Ask whether the benefits of combining these medications outweigh the risks for your specific situation
- Ask what symptoms to watch for that would indicate the interaction is causing problems
- Ask whether any dosage adjustments are needed
- Never stop or change either medication without first consulting your healthcare provider