Is it appropriate to discontinue isosorbide (isosorbide mononitrate) in patients with hypotension who are chest pain-free?

Discontinuation of Isosorbide in Hypotensive, Chest Pain-Free Patients

Yes, it is appropriate to discontinue isosorbide mononitrate in patients with hypotension who are chest pain-free, as hypotension is a recognized contraindication to nitrate therapy. 1

Rationale for Discontinuation

• Severe hypotension is a significant concern with isosorbide use, as noted in the FDA drug label which states: "Severe hypotension, particularly with upright posture, may occur with even small doses of isosorbide dinitrate. This drug should therefore be used with caution in patients who may be volume depleted or who, for whatever reason, are already hypotensive." 1

• The 2017 ACC/AHA/HFSA guidelines specifically recommend against routine use of nitrates in heart failure with preserved ejection fraction (HFpEF), noting that the NEAT-HFpEF trial found no beneficial effects on activity levels, quality of life, exercise tolerance, or NT-proBNP levels. 2

Clinical Decision Algorithm

1. Assess current blood pressure status:

   • If systolic BP <90 mmHg, discontinue isosorbide immediately 1
   • If patient has symptomatic hypotension (dizziness, lightheadedness), discontinue isosorbide

2. Evaluate chest pain status:

   • If patient has been chest pain-free, the primary indication for nitrate therapy may no longer be present
   • Absence of anginal symptoms suggests the potential benefit no longer outweighs the risk of hypotension

3. Consider the original indication for isosorbide:

   • For patients who were taking isosorbide for angina and are now chest pain-free with hypotension, discontinuation is appropriate
   • For African American patients with heart failure who were on hydralazine-isosorbide combination, consider consulting cardiology before discontinuation 2

Important Considerations

• Monitor for rebound phenomena: While uncommon with proper tapering, abrupt discontinuation during long-term isosorbide treatment may exacerbate anginal symptoms in some patients 3

• Tapering recommendation: Consider gradual dose reduction rather than abrupt discontinuation if the patient has been on long-term therapy to minimize risk of symptom recurrence 4

• Alternative therapies: For patients with angina and hypotension who require ongoing anti-anginal therapy, consider consulting cardiology for alternative options 5

• Documentation: Clearly document the reason for discontinuation (hypotension), current chest pain-free status, and instructions for monitoring after discontinuation

Potential Pitfalls

• Rebound angina: In some patients, particularly those on long-term nitrate therapy, abrupt withdrawal can lead to rebound angina. A small study found that 3 out of 32 patients had to be hospitalized due to sudden deterioration of symptoms on withdrawal of isosorbide mononitrate 4

• Misinterpreting hypotension: Ensure hypotension is not due to other causes (dehydration, other medications) before attributing it to isosorbide

• Special populations: In patients with heart failure, particularly African Americans on the hydralazine-isosorbide combination for HFrEF, the decision to discontinue should be made more cautiously as this combination has shown mortality benefits in this specific population 2

By following this approach, you can safely discontinue isosorbide in hypotensive, chest pain-free patients while minimizing risks of adverse outcomes.