Imdur

Imdur (isosorbide mononitrate) is an extended-release nitrate medication indicated for the prevention of angina pectoris due to coronary artery disease. As a potent vasodilator, it primarily works by reducing cardiac preload and afterload, thereby decreasing myocardial oxygen demand. This medication is designed for prophylactic use and is not intended for the acute relief of angina attacks. Its once-daily dosing regimen offers convenience and supports adherence in long-term management strategies for chronic stable angina.

Features

• Contains isosorbide mononitrate as the active pharmaceutical ingredient
• Extended-release formulation for sustained 24-hour plasma concentrations
• Available in multiple strengths including 30 mg, 60 mg, and 120 mg tablets
• Designed for oral administration with or without food
• Manufactured under strict pharmaceutical quality control standards
• Bioequivalent to reference listed drugs with established pharmacokinetic profile

Benefits

• Provides prolonged prophylaxis against angina episodes through sustained vasodilation
• Reduces frequency and severity of angina attacks with consistent daily dosing
• Decreases myocardial oxygen demand by reducing preload and afterload
• Offers convenient once-daily dosing to support long-term treatment adherence
• May improve exercise tolerance and quality of life in patients with chronic angina
• Complements other antianginal therapies in comprehensive CAD management

Common use

Imdur is primarily prescribed for the prophylactic management of angina pectoris in patients with documented coronary artery disease. It is typically used as part of a comprehensive treatment plan that may include beta-blockers, calcium channel blockers, antiplatelet agents, and lifestyle modifications. The medication is particularly valuable for patients who experience frequent angina episodes despite conventional therapy or those who require additional angina prophylaxis beyond first-line treatments. Clinical use is generally reserved for stable angina patterns rather than unstable or variant angina presentations.

Dosage and direction

The recommended initial dosage for most patients is 30 mg or 60 mg once daily, typically administered 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, though most patients achieve optimal effect at 60-120 mg daily. Tablets should be swallowed whole with a glass of water and should not be crushed, chewed, or divided. Administration with food may help minimize potential headache side effects. Dose timing should be consistent daily to maintain stable plasma concentrations.

Precautions

Patients should be advised that Imdur is not intended for acute angina relief and sublingual nitroglycerin should be kept available for breakthrough angina. Orthostatic hypotension may occur, particularly when rising quickly from sitting or lying positions. Alcohol consumption should be limited as it may potentiate hypotensive effects. Tolerance to nitrate effects may develop with continuous therapy; a nitrate-free interval of 10-12 hours is recommended to maintain efficacy. Patients with hypovolemia, hypotension, or increased intracranial pressure require careful monitoring. Caution is advised in elderly patients who may be more sensitive to hypotensive effects.

Contraindications

Imdur is contraindicated in patients with known hypersensitivity to nitrates or any component of the formulation. It must not be used in patients taking phosphodiesterase inhibitors (such as sildenafil, tadalafil, or vardenafil) due to the risk of profound hypotension. Additional contraindications include severe anemia, increased intracranial pressure, and circulatory failure or shock. The medication is not recommended in patients with acute myocardial infarction complicated by congestive heart failure or low filling pressures.

Possible side effects

The most common adverse reaction is headache (occurring in >30% of patients), which often diminishes with continued therapy. Other frequently reported side effects include dizziness (≈8%), nausea (≈6%), and hypotension (≈5%). Less common reactions may include flushing, syncope, reflex tachycardia, and cutaneous vasodilation. Gastrointestinal discomfort and weakness have been reported in some patients. Severe adverse effects are rare but may include marked hypotension, paradoxical angina, or methemoglobinemia in susceptible individuals.

Drug interaction

Concomitant use with phosphodiesterase-5 inhibitors may cause severe hypotension and is absolutely contraindicated. Antihypertensive agents, calcium channel blockers, beta-blockers, and diuretics may potentiate hypotensive effects. Alcohol and vasodilators may enhance orthostatic hypotension. Aspirin may increase nitrate bioavailability while acetylcysteine may potentiate vasodilatory effects. Hepatic metabolism involves multiple pathways, though significant cytochrome-mediated interactions are not well documented.

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 such cases, 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, and patients should be educated on establishing a routine to minimize missed doses.

Overdose

Nitrate overdose manifests primarily as vasodilation leading to severe hypotension, syncope, persistent throbbing headache, dizziness, palpitations, visual disturbances, and flushing. Methemoglobinemia may occur with massive overdose. Management includes elevation of legs to promote venous return, administration of intravenous fluids, and supportive care. Alpha-adrenergic agonists may be considered for refractory hypotension. Methylene blue may be indicated for methemoglobinemia exceeding 30%. Hemodialysis is not effective due to extensive tissue 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, light, and excessive heat. Keep out of reach of children and pets. Do not transfer tablets to other containers as this may affect stability. Discard any medication that has expired or shows signs of deterioration. Do not flush medications down the toilet or pour down a drain unless instructed to do so.

Disclaimer

This information is provided for educational purposes only and does not constitute medical advice. Treatment decisions should be made in consultation with a qualified healthcare professional based on individual patient characteristics. The prescribing physician should be familiar with complete prescribing information and current clinical guidelines. Patients should not alter their medication regimen without medical supervision.

Reviews

Clinical studies demonstrate that Imdur significantly reduces angina frequency and nitroglycerin consumption compared to placebo. In randomized controlled trials, approximately 70% of patients showed improvement in exercise tolerance and angina frequency. Many clinicians report good patient acceptance due to the once-daily dosing schedule. Some patients note that initial headaches typically subside within the first week of therapy. The extended-release formulation is generally regarded as providing more stable plasma concentrations than immediate-release nitrate preparations.