From the Guidelines
Isosorbide mononitrate is recommended for the treatment of angina at a dosage of 20 mg twice daily, as stated in the guidelines 1. The medication comes in two main forms: isosorbide dinitrate (Isordil, Dilatrate-SR) and isosorbide mononitrate (Imdur, Monoket). These medications work as nitrates that dilate blood vessels, improving blood flow to the heart and reducing the workload on the heart. Key points to consider when prescribing isosorbide include:
- Maintaining a nitrate-free interval (usually overnight) to prevent tolerance development
- Common side effects such as headache, dizziness, and hypotension
- Avoiding concomitant use with phosphodiesterase-5 inhibitors (like Viagra) due to the risk of dangerous drops in blood pressure
- Mechanism of action involves releasing nitric oxide, leading to vasodilation and reduced cardiac preload and myocardial oxygen demand It's essential to note that while isosorbide is effective for angina, its use in other conditions like heart failure with preserved ejection fraction (HFpEF) may not be recommended, as seen in the NEAT-HFpEF trial 1.
In terms of specific dosing, the guidelines suggest:
- Isosorbide mononitrate: 20 mg twice daily
- Isosorbide dinitrate: 5-40 mg, 2 or 3 times daily These dosages may vary depending on the formulation and individual patient needs, as outlined in the guidelines 1.
Overall, isosorbide is a valuable medication for the treatment of angina, and its use should be guided by the most recent and highest-quality evidence, such as the guidelines from the American College of Cardiology and American Heart Association 1.
From the FDA Drug Label
Isosorbide mononitrate extended-release tablets are indicated for the prevention of angina pectoris due to coronary artery disease. The use of Isosorbide mononitrate is for the prevention of angina pectoris due to coronary artery disease 2.
- It is not used to abort an acute anginal episode.
From the Research
Use of Isosorbide Mononitrate
- Isosorbide mononitrate is used to prevent angina (chest pain) in patients with certain heart diseases 3, 4, 5, 6, 7.
- It works by relaxing the blood vessels, making it easier for blood to flow to the heart muscle, and reducing the amount of oxygen the heart muscle needs 3.
- Isosorbide mononitrate is effective in terminating acute attacks of angina pectoris and in the prophylaxis of symptomatic and asymptomatic myocardial ischemia 3.
- It is also used to improve exercise tolerance and reduce the frequency of anginal attacks in patients with chronic stable angina pectoris 4, 6.
Administration and Dosage
- Isosorbide mononitrate can be administered orally, and the dosage may vary depending on the patient's condition and response to treatment 4, 6.
- 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.
- The most effective way to prescribe isosorbide-5-mononitrate for angina pectoris appears to be the conventional formulation in a dose of 20 mg two or three times a day 4.
Efficacy and Safety
- Isosorbide mononitrate has been shown to be effective in reducing the frequency of anginal attacks and improving exercise tolerance in patients with chronic stable angina pectoris 6.
- It is well tolerated, with minimal side effects, and serious adverse effects are observed in a small percentage of patients 6.
- Isosorbide mononitrate does not differ significantly from isosorbide dinitrate in reduction of anginal attacks and increase in exercise tolerance, but the effective dose of isosorbide mononitrate may be lower, making it more cost-effective 7.