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Isosorbide Dinitrate
ℹ️ About
Always check the BNF link here 📖 for the latest guidance.
⚙️ Mode of Action
- Nitric oxide (NO) donor → increases intracellular cGMP in vascular smooth muscle → vasodilation (mainly venous, but also arterial at higher doses) → reduced preload, afterload, and myocardial oxygen demand.
💊 Indications & Dose
- Acute angina / left ventricular failure: IV infusion (Isoket®) initially 2–10 mg/hour, increased as needed up to 20 mg/hour with close haemodynamic monitoring.
- Chronic stable angina (PO): 20–40 mg orally TDS in divided doses (max 240 mg/day). Ensure a nitrate-free interval to avoid tolerance.
⚠️ Interactions
- Concurrent use with PDE-5 inhibitors (sildenafil, tadalafil, vardenafil) may cause severe, potentially fatal hypotension 💥.
- Potentiates effects of other antihypertensives and alcohol.
🔎 Cautions
- Low blood pressure or hypovolaemia.
- Severe aortic stenosis, hypertrophic obstructive cardiomyopathy (HOCM), pericardial tamponade 🫀.
- Close monitoring required if given IV or sublingually.
🚫 Contraindications
- Marked hypotension, shock, or hypovolaemia.
- Severe aortic stenosis or other obstructive cardiomyopathies.
- Concurrent PDE-5 inhibitor use.
❗ Side Effects
- Headache (very common) 🤕
- Reflex tachycardia 💓
- Hypotension, dizziness, flushing 📉
- Tolerance with continuous therapy >24h (hence nitrate-free period needed).
📚 References
| The content on this website is provided for educational and informational purposes only to support exam preparation (e.g., MLA, MRCP, USMLE) and learning. This is NOT medical advice, diagnosis, treatment, or professional guidance. It does not replace consultation with a qualified healthcare professional, official guidelines (e.g., NICE, GMC, BNF), or supervised clinical practice. Always verify information with current, authoritative sources. Makindo and its contributors accept no liability for any reliance on this content, including errors, omissions, or any resulting harm, loss, or consequences. By using this site, you agree to these terms. |
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