Isosorbide Mononitrate (ISMN) Dosing in Chronic Kidney Disease
The standard dosing of isosorbide mononitrate for patients with chronic kidney disease does not require adjustment, with the recommended starting dose of 30 mg once daily, which may be increased to 120 mg once daily as needed. 1
Standard Dosing Recommendations
- The FDA-approved dosing for isosorbide mononitrate extended-release tablets begins at 30 mg once daily (given as a single 30 mg tablet or as 1/2 of a 60 mg tablet) or 60 mg once daily (given as a single tablet) 1
- After several days, the dosage may be increased to 120 mg once daily (given as a single 120 mg tablet or as two 60 mg tablets) 1
- In rare cases, doses up to 240 mg may be required 1
- The daily dose should be taken in the morning upon arising 1
Considerations in CKD Patients
Hemodynamic Effects
- ISMN causes vasodilation by releasing nitric oxide, which can potentially affect renal hemodynamics 2
- Studies in cirrhotic patients (not specifically CKD) have shown that acute administration of ISMN can temporarily reduce glomerular filtration rate, particularly in patients with ascites 3, 4
- However, long-term administration of ISMN has not been shown to impair renal function 4
Monitoring Recommendations
- Monitor blood pressure closely after initiation, as ISMN can cause hypotension 2
- In patients with advanced CKD (eGFR <15 ml/min per 1.73 m²), consider starting at the lower end of the dosing range (30 mg daily) and titrate cautiously 5
- If the patient is also taking renin-angiotensin system inhibitors (RASi), be particularly vigilant about blood pressure monitoring as both medications can cause hypotension 5
Special Considerations
- For patients on hemodialysis, ISMN has been studied at doses of 30-120 mg daily without requiring specific dose adjustments 2
- In a study of maintenance hemodialysis patients with hypertension and left ventricular hypertrophy, ISMN at doses of 30-120 mg daily was found to be safe and effective 2
Potential Benefits in CKD Population
- In hemodialysis patients, ISMN has been shown to help control blood pressure and improve left ventricular hypertrophy 2
- The incidence of adverse events in hemodialysis patients was reported to be low (1.4%) 2
Common Pitfalls and Caveats
- Avoid rapid dose escalation in CKD patients to prevent symptomatic hypotension 2
- Be cautious when combining ISMN with other antihypertensive medications, particularly in patients with advanced CKD 5
- If the patient develops symptomatic hypotension, consider reducing the dose rather than discontinuing the medication completely 2
- ISMN should not be chewed or crushed and should be swallowed with fluid 1
In conclusion, while specific CKD dosing guidelines for ISMN are not extensively documented in major nephrology guidelines, the available evidence suggests that standard dosing can be used with appropriate monitoring, starting at the lower end of the dosing range in advanced CKD patients.