Drug interactions
Nitroglycerin rectal + Prazosin
Severity: Moderate
Nitroglycerin rectal and Prazosin: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Nitroglycerin relaxes vascular smooth muscle and prazosin blocks alpha-1 mediated vasoconstriction. Together they can cause marked hypotension and syncope, particularly on standing.
What this interaction means in plain words
Nitroglycerin rectal and Prazosin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Additive vasodilatory effects through nitric oxide-mediated venodilation and alpha-1 adrenergic blockade.
What to do
Monitor blood pressure, including standing readings, when the combination is started or doses change. Advise patients to rise slowly and to sit or lie down if lightheaded.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Prazosin
- Alfuzosin + Prazosin Major
- Amifostine + Prazosin Major
- Avanafil + Prazosin Major
- Doxazosin + Prazosin Major
- Dutasteride-tamsulosin + Prazosin Major
- Phenoxybenzamine + Prazosin Major
Frequently asked questions
Can I take Nitroglycerin rectal with Prazosin?
MediHelp rates the interaction as moderate. Nitroglycerin rectal and Prazosin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Nitroglycerin relaxes vascular smooth muscle and prazosin blocks alpha-1 mediated vasoconstriction. Together they can cause marked hypotension and syncope, particularly on standing.
How serious is the interaction between Nitroglycerin rectal and Prazosin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood pressure, including standing readings, when the combination is started or doses change. Advise patients to rise slowly and to sit or lie down if lightheaded.
What other medicines interact with Prazosin?
MediHelp also lists interactions of Prazosin with, for example, Alfuzosin, Amifostine, Avanafil. The full list is on the Prazosin page.
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