From the Guidelines
It is generally not recommended to take Imdur (isosorbide mononitrate) and Nifedipine at the same time due to the potential for increased hypotensive effects. However, if co-administration is necessary, it should be done with caution and under close medical supervision 1.
Key Considerations
- The patient's blood pressure and heart rate should be closely monitored, and the doses of both medications may need to be adjusted.
- Typically, Imdur is taken in doses of 30-60 mg once daily, and Nifedipine is taken in doses of 30-90 mg once daily.
- The patient's healthcare provider should carefully evaluate the benefits and risks of concurrent therapy and consider alternative treatment options if necessary.
Important Warnings
- Rapid-release, short-acting dihydropyridines (e.g., nifedipine) must be avoided in the absence of concomitant beta blockade because of increased adverse potential 1.
- Verapamil and diltiazem should be avoided in patients with pulmonary edema or evidence of severe LV dysfunction.
Evidence Summary
The use of calcium channel blockers, including nifedipine, in patients with unstable angina/non-ST-elevation myocardial infarction (UA/NSTEMI) has been studied in several randomized trials, with mixed results 1. While some studies have suggested a benefit of adding nifedipine to beta blockers, others have raised concerns about the potential for increased adverse effects. Therefore, caution is advised when co-administering Imdur and Nifedipine, and careful monitoring of the patient's condition is essential.
From the Research
Combination Therapy with Isosorbide Mononitrate and Nifedipine
- The use of Isosorbide mononitrate (Imdur) and Nifedipine in combination has been studied in various clinical trials 2, 3.
- A study published in the American Heart Journal in 1990 found that nifedipine alone was more effective than isosorbide dinitrate alone in reducing angina attacks and improving exercise tolerance 2.
- The same study found that the combination of isosorbide dinitrate and nifedipine did not demonstrate a significant advantage over nifedipine alone compared to isosorbide dinitrate alone 2.
- Another study published in the Lancet in 1991 found that the addition of nifedipine and isosorbide mononitrate to atenolol did not confer a significant advantage over beta-blockade alone in patients with stable angina 3.
- However, the study found that the combination of atenolol and isosorbide mononitrate resulted in a longer total exercise duration compared to atenolol alone or atenolol plus nifedipine 3.
Efficacy and Safety of Isosorbide Mononitrate
- Isosorbide mononitrate (Imdur) has been shown to be effective in reducing angina symptoms and improving exercise tolerance in patients with chronic stable angina 4, 5.
- The drug has a rapid onset of action and a sustained release formulation, which provides effective antianginal prophylaxis for up to 12 hours 4, 5.
- Isosorbide mononitrate is generally well tolerated, with the most common adverse event being headache, which is usually mild to moderate and improves with long-term therapy 4.
Combination Therapy with Other Drugs
- The combination of isosorbide-5-mononitrate with amlodipine has been shown to be effective in reducing blood pressure and improving exercise tolerance in patients with ischemic-hypertensive cardiopathy 6.
- The combination of isosorbide mononitrate with nifedipine has been studied, but the results are inconsistent, and more research is needed to determine the efficacy and safety of this combination 2, 3.