From the Guidelines
Imdur (isosorbide mononitrate) and nitroglycerin should not be given together due to the risk of severe hypotension and decreased quality of life. The combination of these two medications can cause dangerous drops in blood pressure, leading to dizziness, fainting, and inadequate blood flow to vital organs, which can negatively impact morbidity, mortality, and quality of life 1. Both medications are nitrates that work by dilating blood vessels, and using them simultaneously creates an additive effect that significantly increases the risk of severe hypotension. According to the 2025 ACC/AHA/ACEP/NAEMSP/SCAI guideline for the management of patients with acute coronary syndromes, nitrates should be used with caution and patients should maintain a nitrate-free interval between doses of different nitrate medications as prescribed by their healthcare provider 1. If you are currently taking one nitrate medication and experiencing chest pain, consult your healthcare provider before adding another nitrate. In emergency situations where you are taking Imdur and experiencing chest pain, contact your healthcare provider immediately for guidance on whether it's safe to use nitroglycerin. Some key considerations for nitroglycerin use include:
- Starting with a low dose (0.3 or 0.4 mg every 5 min as needed up to a total of 3 doses) for sublingual administration
- Using intravenous nitroglycerin with caution, starting at 10 μg/min and titrating to pain relief and hemodynamic tolerability
- Avoiding use in suspected RV infarction, SBP <90 mm Hg or a change in SBP >30 mm Hg below baseline
- Monitoring closely for adverse effects such as headache and hypotension 1. The dangerous interaction between Imdur and nitroglycerin occurs because both medications increase nitric oxide levels in the body, causing excessive vasodilation when combined. Therefore, it is crucial to prioritize caution and consult with a healthcare provider before using these medications together to minimize the risk of adverse effects and ensure optimal management of acute coronary syndromes.
From the Research
Administration of Imdur and Nitroglycerin
- Imdur, also known as isosorbide mononitrate, is a medication used to prevent angina attacks 2, 3, 4.
- Nitroglycerin is another medication used to treat angina attacks by relaxing the blood vessels and improving blood flow to the heart 5, 6.
Combination Therapy
- There is no direct evidence in the provided studies that specifically addresses the combination of Imdur and nitroglycerin 5, 6, 2, 3, 4.
- However, studies have shown that nitrates, including nitroglycerin, can be used in combination with other medications, such as calcium channel blockers, to treat angina pectoris 5, 6.
- One study found that the addition of a nitrate, isosorbide mononitrate, to a beta-blocker, atenolol, resulted in a slight advantage in favor of the nitrate, but the combination of multiple drugs did not confer a substantial advantage over optimum beta-blockade as monotherapy 3.
Dosage and Administration
- Imdur can be administered once daily, and its effects can last for at least 9 hours after the dose 4.
- Nitroglycerin can be administered sublingually, and its effects can last for a shorter duration, requiring repeated administration as needed 5.
- The dosage and administration of Imdur and nitroglycerin should be individualized and based on the patient's response to treatment, as well as their medical history and other medications they are taking 2, 3, 4.