Drug interactions
isosorbide mononitrate + sildenafil
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.
Overview
Concurrent use can cause profound, potentially life‑threatening hypotension with risk of syncope and myocardial ischemia/infarction.
Mechanism of action
Additive vasodilation: organic nitrates increase NO→cGMP; sildenafil inhibits PDE5, preventing cGMP breakdown, leading to marked BP reduction.
Clinical management
Do not coadminister. Avoid nitrates for at least 24 hours after sildenafil. If nitrate use is unavoidable in an emergency, ensure ≥24 h since sildenafil and closely monitor BP/HR; use minimal nitrate dose and supportive care.
Drug reference
References
- Viagra (sildenafil citrate) Prescribing Information — FDA Label
- Isosorbide Mononitrate Prescribing Information — FDA Label
- Sildenafil and Nitrates — Drug Interaction Monograph — Lexicomp
Frequently asked questions
Can I take isosorbide mononitrate with sildenafil?
The interaction is rated: Contraindicated. Concurrent use can cause profound, potentially life‑threatening hypotension with risk of syncope and myocardial ischemia/infarction.
How serious is the interaction between isosorbide mononitrate and sildenafil?
The interaction is rated: Contraindicated. Evidence level: High.
How is the interaction between isosorbide mononitrate and sildenafil managed?
Do not coadminister. Avoid nitrates for at least 24 hours after sildenafil. If nitrate use is unavoidable in an emergency, ensure ≥24 h since sildenafil and closely monitor BP/HR; use minimal nitrate dose and supportive care.
Why do isosorbide mononitrate and sildenafil interact?
Additive vasodilation: organic nitrates increase NO→cGMP; sildenafil inhibits PDE5, preventing cGMP breakdown, leading to marked BP reduction.
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