From the Research
The maximum daily dose of isosorbide dinitrate (ISDN) for chest pain is typically 120-160 mg per day, divided into multiple doses. For immediate-release oral tablets, patients usually start with 5-20 mg taken 2-3 times daily, with the dosage adjusted based on response 1. For sustained-release formulations, 40 mg taken 1-2 times daily is common, with a maximum of 80 mg per dose. When using sublingual ISDN for acute angina, patients can take 2.5-5 mg as needed, waiting 5-10 minutes between doses if pain persists, but should not exceed 3 doses within a 15-30 minute period. To prevent nitrate tolerance, a nitrate-free interval of 10-14 hours daily (typically overnight) is recommended 1.
Key Considerations
- ISDN works by relaxing vascular smooth muscle, leading to vasodilation, which reduces cardiac workload and oxygen demand while improving coronary blood flow.
- Side effects may include headache, dizziness, and hypotension.
- Patients should be cautioned not to use phosphodiesterase-5 inhibitors (like sildenafil) concurrently with nitrates due to the risk of severe hypotension.
- The goal of therapy is to provide symptomatic relief, improve patient quality of life, and prevent subsequent angina or myocardial infarction that could lead to sudden death 2.
Dosage and Administration
- For immediate-release oral tablets: 5-20 mg taken 2-3 times daily.
- For sustained-release formulations: 40 mg taken 1-2 times daily, with a maximum of 80 mg per dose.
- For sublingual ISDN: 2.5-5 mg as needed, waiting 5-10 minutes between doses if pain persists, but should not exceed 3 doses within a 15-30 minute period.
Prevention of Nitrate Tolerance
- A nitrate-free interval of 10-14 hours daily (typically overnight) is recommended to prevent nitrate tolerance 1.