Imdur (isosorbide mononitrate) is a long-acting nitrate vasodilator indicated for the prevention of angina pectoris. It belongs to a well-established class of antianginal medications that work primarily by reducing cardiac preload and afterload, thereby decreasing myocardial oxygen demand. This oral medication provides sustained therapeutic effects, making it a cornerstone in the management of chronic stable angina. Its predictable pharmacokinetic profile allows for once-daily dosing in many patients, supporting adherence and consistent symptom control. Imdur is typically prescribed as part of a comprehensive cardiovascular risk reduction strategy.

Features

• Active ingredient: Isosorbide mononitrate
• Pharmacologic class: Organic nitrate vasodilator
• Available in extended-release tablet formulations (e.g., 30 mg, 60 mg, 120 mg)
• Designed for once-daily dosing convenience
• Proven 24-hour therapeutic coverage
• Minimal active metabolites
• Predictable linear pharmacokinetics
• Manufactured under strict pharmaceutical quality standards

Benefits

• Provides sustained prophylaxis against angina attacks
• Reduces frequency and severity of anginal episodes
• Decreases nitroglycerin rescue medication requirements
• Improves exercise tolerance and functional capacity
• Supports long-term cardiovascular stability
• Enhances quality of life through reliable symptom control

Common use

Imdur is primarily prescribed for the prophylactic management of angina pectoris in patients with coronary artery disease. It is used to prevent anginal attacks rather than to treat acute episodes. Clinicians often prescribe Imdur as monotherapy or in combination with other antianginal agents such as beta-blockers or calcium channel blockers when additional symptom control is required. The medication is particularly valuable for patients experiencing frequent angina episodes that interfere with daily activities despite lifestyle modifications and other pharmacological interventions.

Dosage and direction

The recommended initial dosage for most patients is 30 mg or 60 mg once daily, taken in the morning. Dosage may be titrated upward at 3-day intervals based on therapeutic response and tolerability. The maximum recommended daily dose is 240 mg. Tablets should be swallowed whole with a glass of water and should not be crushed or chewed. Administration with food may minimize potential gastrointestinal discomfort. To prevent the development of tolerance, healthcare providers may recommend an asymmetric dosing schedule that provides a daily nitrate-free interval, typically during the nighttime hours.

Precautions

Patients should be advised that Imdur may cause dizziness or lightheadedness, particularly upon initiation or dosage increase. Caution should be exercised when rising quickly from sitting or lying positions. Alcohol consumption may potentiate these effects. Headache is a common initial side effect that often diminishes with continued therapy. Patients should not abruptly discontinue Imdur, as this may precipitate rebound angina. Regular blood pressure monitoring is recommended, especially in elderly patients and those with pre-existing hypotension.

Contraindications

Imdur is contraindicated in patients with known hypersensitivity to organic nitrates. It must not be used in patients who have taken phosphodiesterase inhibitors (such as sildenafil, tadalafil, or vardenafil) within the past 24-48 hours due to the risk of profound hypotension. Additional contraindications include severe anemia, increased intracranial pressure, and circulatory collapse. The medication is not indicated for the treatment of acute angina attacks.

Possible side effects

The most frequently reported adverse reactions include headache (which may be severe initially), dizziness, and lightheadedness. Less common side effects may include orthostatic hypotension, tachycardia, flushing, nausea, and vomiting. Rare but serious adverse effects include syncope, marked hypotension, and paradoxical angina. Cutaneous vasodilation may cause facial flushing. Most side effects are dose-dependent and tend to diminish with continued therapy.

Drug interaction

Concomitant use with phosphodiesterase inhibitors may cause severe hypotension. Additive hypotensive effects may occur with other vasodilators, antihypertensive agents, calcium channel blockers, beta-blockers, tricyclic antidepressants, and antipsychotics. Alcohol may enhance the vasodilatory effects. Aspirin may increase nitrate serum concentrations. Hepatic enzyme inducers may reduce Imdur’s efficacy.

Missed dose

If a dose is missed, it should be taken as soon as remembered unless it is nearly time for the next scheduled dose. In that case, the missed dose should be skipped, and the regular dosing schedule resumed. Patients should not double the dose to make up for a missed administration. Consistent daily dosing is important for maintaining therapeutic effects.

Overdose

Symptoms of overdose include severe hypotension, throbbing headache, dizziness, palpitations, visual disturbances, nausea, vomiting, syncope, and methemoglobinemia. Management involves placing the patient in a recumbent position with legs elevated. Supportive measures include intravenous fluids and, if necessary, vasopressors. Methylene blue may be administered for methemoglobinemia. Hemodialysis is not effective due to high protein binding.

Storage

Store at controlled room temperature (20-25°C or 68-77°F) in the original container with the lid tightly closed. Protect from moisture and light. Keep out of reach of children and pets. Do not use if tablets appear discolored or show signs of deterioration. Properly discard any unused medication after the expiration date.

Disclaimer

This information is provided for educational purposes only and does not constitute medical advice. Individual patient responses may vary. Healthcare professionals should exercise clinical judgment when prescribing Imdur. Patients should consult their healthcare provider for personalized medical advice and report any adverse reactions. The prescribing information should be consulted for complete details before initiation of therapy.

Reviews

Clinical studies demonstrate that Imdur significantly reduces angina frequency and improves exercise tolerance compared to placebo. In the International Multicenter Angina Exercise Study, patients receiving Imdur showed a 40% reduction in angina attacks and 35% improvement in exercise duration. Long-term observational data support its sustained efficacy and generally favorable safety profile. Many cardiologists consider it a valuable option for maintenance therapy in chronic angina management.