Isosorbide Mononitrate Mechanism and Clinical Applications
Mechanism of Action
- Isosorbide mononitrate is a nitrate vasodilator that works by dilating normal and atherosclerotic epicardial coronary arteries, dilating smaller arteries that constrict with certain stressors, promoting dilation of large coronary arteries, enhancing collateral flow and redistributing coronary blood flow to ischemic regions, and inhibiting platelet aggregation, though the clinical significance of this action is not well defined, as recommended by the American College of Cardiology 1
Clinical Applications
Heart Failure
- In heart failure patients, hydralazine plus isosorbide dinitrate (including mononitrate formulations) may be beneficial in specific populations, particularly effective in African American patients with NYHA class III or IV heart failure with reduced ejection fraction, as shown by the American Heart Association 2, 3, 4
- This combination has been shown to reduce mortality in African American patients with advanced heart failure, with a strength of evidence supported by multiple studies 4
- The benefit is presumed to be related to enhanced nitric oxide bioavailability, as suggested by the American College of Cardiology 5
Important Precautions and Contraindications
- Contraindicated with phosphodiesterase inhibitors, such as sildenafil and tadalafil, due to the risk of profound hypotension, myocardial infarction, and even death, as warned by the American College of Cardiology 1
- Should be avoided in patients with severe hypotension (systolic BP <90 mmHg), as recommended by the European Society of Cardiology 6
- Use with caution in patients with aortic stenosis as they may demonstrate marked hypotension following nitrate administration, as advised by the American College of Cardiology 1