What is the Difference Between Isosorbide Mononitrate and Isosorbide Dinitrate?

Isosorbide mononitrate and isosorbide dinitrate are both nitrate medications used to prevent angina symptoms and treat heart failure, but they have some differences in their pharmacokinetic properties and usage:

1. Elimination Half-life: The elimination half-life of isosorbide dinitrate is 1 hour, while the elimination half-life of isosorbide mononitrate is 5 to 6 hours.
2. Bioavailability: Isosorbide mononitrate, an active metabolite of isosorbide dinitrate, does not undergo the first-pass effect, and its bioavailability is 100% after oral administration.
3. Dosage Forms: Both isosorbide mononitrate and isosorbide dinitrate are available in standard tablets and slow-release (modified release) tablets.
4. Tolerance: When isosorbide dinitrate is administered in 3 to 4 doses daily, nitrate tolerance can develop, rendering the agent less efficacious.

Both medications work by widening blood vessels (veins and arteries) to increase blood supply to the heart, which helps reduce chest pain. In heart failure, these medications relax the blood vessels, making it easier for the heart to pump blood around the body. Your doctor will prescribe the most suitable medication for your specific needs and condition.

Comparative Table: Isosorbide Mononitrate vs Isosorbide Dinitrate

Here is a table comparing the differences between isosorbide mononitrate and isosorbide dinitrate:

Both isosorbide mononitrate and isosorbide dinitrate are nitrate medications that work by widening blood vessels to prevent angina symptoms and are not used to treat a current angina attack. The main differences between the two are their bioavailability, elimination half-life, and approved indications. Isosorbide mononitrate has a higher bioavailability and a longer elimination half-life than isosorbide dinitrate. Additionally, isosorbide dinitrate is also recommended for heart failure, while isosorbide mononitrate is not.