From the Guidelines
Isosorbide mononitrate should be dosed at 20 mg twice daily for the immediate-release formulation, with doses taken 7 hours apart, as indicated in the most recent guidelines 1. The dosing of Isosorbide Mononitrate (IMN) is crucial for effective management of angina and other cardiovascular conditions.
- The immediate-release formulation is typically dosed at 20 mg twice daily, with a 7-hour interval between doses to prevent nitrate tolerance.
- For extended-release formulations, the usual dose is 60 to 240 mg once daily, as specified in the guidelines 1. Key considerations in dosing IMN include:
- Starting with lower doses and titrating upward based on patient response and tolerance.
- Maintaining a daily nitrate-free interval of 10-14 hours to minimize tolerance development.
- Being aware of potential side effects, such as headache, dizziness, and hypotension, and contraindications, including concurrent use with phosphodiesterase-5 inhibitors. The most recent guidelines from 2022 1 do not provide specific dosing recommendations for IMN, but earlier guidelines from 2013 1 suggest the above dosing regimens.
- It is essential to consult the latest clinical guidelines and individual patient needs when determining the optimal dosing strategy for IMN.
- The medication works by relaxing vascular smooth muscle through nitric oxide release, causing vasodilation that reduces cardiac workload and improves oxygen supply to the heart.
- Patients should take the medication consistently and avoid abrupt discontinuation to maximize its benefits and minimize risks.
From the FDA Drug Label
DOSAGE AND ADMINISTRATION The recommended starting dose of isosorbide mononitrate extended-release tablets, USP is 30 mg (given as a single 30 mg tablet or as 1/2 of a 60 mg tablet) or 60 mg (given as a single tablet) once daily. After several days, the dosage may be increased to 120 mg (given as a single 120 mg tablet or as two 60 mg tablets) once daily. Rarely, 240 mg may be required. The daily dose of isosorbide mononitrate extended-release tablets, USP should be taken in the morning on arising. The dosing for Isosorbide Mononitrate (IMN) is as follows:
- Starting dose: 30 mg or 60 mg once daily
- Increased dose: 120 mg once daily after several days
- Maximum dose: Rarely, 240 mg may be required 2
From the Research
Dosing for Isosorbide Mononitrate (IMN)
- The dosing for Isosorbide Mononitrate (IMN) varies depending on the formulation and the patient's condition 3, 4, 5, 6, 7.
- For conventional formulations, a dose of 20 mg two or three times a day is commonly used 5, 7.
- For sustained-release formulations, such as Imdur, a dose of 60 mg once daily is often recommended 4, 6.
- Studies have shown that once-daily administration of sustained-release IMN can provide effective antianginal prophylaxis for up to 12 hours 6.
- It is generally accepted that a daily low-nitrate interval is required to prevent tolerance development, and a 12-h patch-free interval should prevent tolerance in most patients 3.
Tolerance Development
- Tolerance to IMN can develop rapidly if used in higher doses or with continuous administration 3, 5.
- Intermittent therapy with once-daily ingestion of high-dose sustained-release IMN can prevent the development of tolerance 3.
- Studies have shown that tolerance to IMN does not develop when it is ingested once daily 3, 4.
Efficacy and Safety
- IMN has been shown to be effective in reducing angina frequency and improving exercise tolerance 4, 6, 7.
- The most frequently reported adverse event is headache, which is usually mild to moderate and improves with long-term therapy 6, 7.
- Patient compliance is better with once-daily administration of sustained-release IMN than with twice-daily administration of conventional IMN 6.