Imdur 30 mg Tablets

Brand Name

The medication is commercially known as Imdur, a name widely adopted in the pharmaceutical landscape. This branding identifies it as a reliable choice for specific cardiovascular treatments, distinguishing it within the therapeutic market.

International Non-Proprietary Name (INN)

Globally, Imdur is recognized by its international non-proprietary name, isosorbide mononitrate. This designation highlights the active substance responsible for its clinical effects, ensuring consistency across medical documentation and practice worldwide.

Form of Release

This drug is formulated as extended-release tablets, tailored for oral use. Available in strengths of 30 mg, 60 mg, and occasionally 120 mg, these tablets are engineered to provide a gradual release of the active component, supporting sustained therapeutic action throughout the day.

Composition

The primary active ingredient in Imdur is isosorbide mononitrate, a nitrate compound that drives its vasodilatory properties. Supporting this are excipients including hypromellose, paraffin, silicon dioxide, magnesium stearate, and microcrystalline cellulose, which form the tablet’s matrix for controlled release. Some formulations incorporate a film coating with polyethylene glycol, titanium dioxide, and hydroxypropyl methylcellulose, enhancing stability and ease of swallowing, while trace amounts of colorants may differentiate strengths visually.

Pharmacologic Properties

Pharmacodynamics

Imdur exerts its effects by releasing nitric oxide within vascular smooth muscle cells, prompting relaxation of these tissues. This process reduces tension in both venous and arterial walls, lowering preload and afterload on the heart. By dilating coronary arteries, it enhances blood flow to the myocardium, alleviating oxygen deficits during exertion. The reduction in cardiac workload and improved perfusion make it particularly effective in preventing episodes of chest pain linked to inadequate blood supply, offering a sustained protective mechanism over time.

Pharmacokinetics

Following oral intake, isosorbide mononitrate in Imdur is absorbed efficiently from the gastrointestinal tract, achieving nearly 100% bioavailability due to its resistance to first-pass metabolism. Peak plasma levels are reached within 3 to 6 hours with the extended-release form, influenced by the tablet’s design. It distributes broadly, with a volume of distribution around 0.6 L/kg, and exhibits minimal protein binding. Metabolism occurs in the liver, yielding inactive glucuronide conjugates, which are excreted predominantly through urine. The elimination half-life ranges from 6 to 10 hours, supporting once-daily dosing for consistent therapeutic coverage.

Indications for Use

Diseases and Conditions

Imdur is primarily prescribed for the prophylactic management of angina pectoris resulting from coronary artery disease. It serves to prevent episodes of chest pain in patients with chronic stable angina, reducing the frequency and severity of attacks. Its sustained-release profile makes it suitable for long-term use, supporting patients in maintaining daily activities with less disruption from cardiac symptoms. This medication is not intended for acute relief but rather for ongoing prevention in diagnosed cases.

Contraindications

Conditions Prohibiting Use

Imdur must not be used by individuals with a known sensitivity to isosorbide mononitrate or related nitrates, as allergic reactions could range from skin rashes to systemic distress. It is unsuitable for patients experiencing acute circulatory failure, such as shock or severe hypotension, where further vessel dilation could destabilize blood pressure. Those with recent head trauma or cerebral hemorrhage should avoid it due to risks of increased intracranial pressure. Additionally, severe anemia, closed-angle glaucoma, and hypertrophic obstructive cardiomyopathy preclude its use, as the drug’s effects could worsen these conditions. Concurrent use with phosphodiesterase-5 inhibitors, like sildenafil, is also prohibited due to the potential for profound blood pressure drops.

Method of Administration and Dosage

Administration Guidelines

Imdur tablets are taken orally, ideally in the morning to align with daily activity patterns and minimize nocturnal accumulation. They should be swallowed whole with water, not chewed or crushed, to preserve the extended-release mechanism. Food does not significantly impact absorption, allowing flexibility in timing relative to meals. Patients are advised to maintain a consistent schedule and avoid abrupt discontinuation to prevent rebound effects.

Dosage for Adults and Children

For adults, Imdur typically starts at 30 mg once daily, with potential escalation to 60 mg after a few days based on tolerance and response. In some cases, doses may reach 120 mg daily under medical supervision, though this is less common. A nitrate-free interval, often overnight, helps mitigate tolerance development. Pediatric use is not well-established; when considered, dosing is individualized by specialists, starting as low as 5-10 mg daily, adjusted cautiously due to limited safety data in younger populations.

Dose Adjustment in Specific Conditions

In renal impairment, no standard dose modification is required, as elimination relies primarily on hepatic metabolism, though monitoring for adverse effects is prudent in severe cases. Hepatic dysfunction, particularly advanced stages, may necessitate lower doses or alternative therapies, as reduced metabolism could prolong drug activity and increase side effect risks. Elderly patients often begin at 30 mg, with gradual increases if tolerated, reflecting potential declines in organ function and sensitivity to vasodilatory effects.

Side Effects

Potential Adverse Reactions

Imdur may provoke a variety of unintended responses, most commonly headaches due to cerebral vessel dilation, which often diminish with continued use. Dizziness or lightheadedness can occur, particularly upon standing, linked to blood pressure changes. Gastrointestinal upset, such as nausea or abdominal discomfort, is reported occasionally, as is flushing or warmth in the face and neck. Fatigue and weakness may affect some users, while rare instances of palpitations or worsening angina signal the need for reassessment. Skin reactions like rashes are infrequent but possible, and prolonged therapy might contribute to nitrate tolerance, reducing efficacy over time.

Overdose

Symptoms of Overdose

Excessive intake of Imdur can lead to marked vasodilation, resulting in severe hypotension with symptoms like fainting, cold sweats, or confusion. Rapid or irregular heartbeats may accompany this, alongside persistent headaches or throbbing sensations. Nausea, vomiting, and shortness of breath could emerge, while extreme cases might involve cyanosis or methemoglobinemia, indicated by bluish skin discoloration, reflecting impaired oxygen transport. Immediate attention is required to address these effects.

First Aid Measures

In an overdose scenario, patients should lie flat with legs elevated to support circulation, avoiding further drug intake. Medical assistance should be sought promptly, with administration of intravenous fluids or vasopressors considered to stabilize blood pressure. If methemoglobinemia is suspected, methylene blue may be given under supervision to restore oxygen-carrying capacity. Monitoring vital signs and oxygen levels guides treatment, with supportive care continuing until symptoms resolve fully.

Drug Interactions

Effects on Other Medications

Imdur can amplify the hypotensive effects of other vasodilators, antihypertensives, or nitrates, requiring careful dose coordination to avoid excessive pressure drops. Its combination with phosphodiesterase-5 inhibitors, such as tadalafil or vardenafil, is contraindicated due to risks of life-threatening hypotension. Beta-blockers or calcium channel blockers used concurrently may enhance anti-anginal benefits but need monitoring for additive effects on heart rate or pressure. It does not significantly alter the metabolism of other drugs, as it lacks notable enzyme induction or inhibition properties.

Compatibility with Alcohol and Food

Alcohol consumption with Imdur may intensify vasodilation, leading to dizziness or fainting, and should be moderated or avoided. Food interactions are minimal, though high-fat meals might slightly delay absorption without altering overall efficacy. Patients are encouraged to maintain steady dietary patterns, as abrupt changes in nitrate-rich food intake could influence tolerance development over time.

Special Precautions

Use During Pregnancy and Breastfeeding

Data on Imdur use in pregnancy are limited, with no clear evidence of harm but insufficient studies to confirm safety. It should only be prescribed if benefits outweigh potential fetal risks, with close monitoring advised. Isosorbide mononitrate may enter breast milk in small quantities, though effects on nursing infants are unknown; breastfeeding mothers should consult healthcare providers, potentially pausing lactation or exploring alternatives during treatment.

Impact on Driving and Operating Machinery

Imdur may cause dizziness or fatigue, particularly during initial use or dose adjustments, which could impair the ability to drive or operate machinery. Patients should evaluate their reaction to the medication before engaging in such activities, refraining if symptoms persist, to ensure personal and public safety.

Considerations for Elderly and Pediatric Populations

Elderly individuals may experience heightened sensitivity to Imdur’s hypotensive effects, often starting at lower doses like 30 mg with gradual titration based on tolerance. In children, its application is rare and lacks robust evidence, reserved for exceptional cases under specialist care with conservative dosing to minimize risks. Both groups require personalized adjustments to optimize therapeutic outcomes while reducing adverse reactions.