Imdur

Dosage Forms & Strengths

tablet

• 10mg
• 20mg

tablet, extended release

• 30mg
• 60mg
• 120mg

Angina Pectoris

Prevention of angina pectoris caused by coronary artery disease

Immediate release: 5-10 mg PO twice daily initially (5 mg in small patients) given each dose 7 hr apart; increased to 10 mg PO q12hr by day 2 or 3; maintenance: 20 mg PO q12hr

Extended release: 30-60 mg PO once daily in the morning initially; may be increased to 120 mg PO once daily; wait at least 3 days between increases; if warranted may increase up to 240 mg PO once daily (rare)

Dosing considerations

• Take on empty stomach, 30 minutes before meals or 1 hour after meal
• Take on empty stomach, 30 minutes before or 1 hour after meal
• Extended-release tablet should be swallowed whole; must not be chewed, crushed, or split

Safety and efficacy not established

Angina Pectoris

Start with lowest recommended adult dose

In the U.S.

• Imdur
• Imdur ER
• Ismo
• Monoket

Available Dosage Forms:

• Tablet, Extended Release
• Tablet

Therapeutic Class: Antianginal

Chemical Class: Nitrate

• If you have an allergy to isosorbide mononitrate or any other part of Imdur (isosorbide mononitrate sustained-release tablets).
• If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
• If you are taking any of these drugs: Avanafil, riociguat, sildenafil, tadalafil, or vardenafil.

This is not a list of all drugs or health problems that interact with this medicine.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take Imdur with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

Use this medicine as ordered by your doctor. Read all information given to you. Follow all instructions closely.

• Do not stop taking Imdur all of a sudden without calling your doctor. You may have a greater risk of side effects. If you need to stop this medicine, you will want to slowly stop it as ordered by your doctor.
• If you are taking Imdur (isosorbide mononitrate sustained-release tablets) once a day, take it in the morning when you get up unless your doctor tells you otherwise.
• Swallow whole. Do not chew, break, or crush.
• Some products may be broken in half. Talk with the doctor.

What do I do if I miss a dose?

• Take a missed dose as soon as you think about it.
• If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
• Do not take 2 doses at the same time or extra doses.

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Dizziness.
• You may have headaches when you start taking this medicine. Most of the time it gets better with time. Do not change how you use Imdur to avoid these headaches. Talk with your doctor for ways to lessen this side effect.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects at http://www.fda.gov/medwatch.

Imdur Tablets are indicated for the prevention of angina pectoris due to coronary artery disease. The onset of action of oral isosorbide mononitrate is not sufficiently rapid for this product to be useful in aborting an acute anginal episode.

General

Severe hypotension, particularly with upright posture, may occur with even small doses of isosorbide mononitrate. This drug should, therefore, be used with caution in patients who may be volume depleted or who, for whatever reason, are already hypotensive. Hypotension induced by isosorbide mononitrate may be accompanied by paradoxical bradycardia and increased angina pectoris.

Nitrate therapy may aggravate the angina caused by hypertrophic cardiomyopathy.

In industrial workers who have had long-term exposure to unknown (presumably high) doses of organic nitrates, tolerance clearly occurs. Chest pain, acute myocardial infarction, and even sudden death have occurred during temporary withdrawal of nitrates from these workers, demonstrating the existence of true physical dependence. The importance of these observations to the routine, clinical use of oral isosorbide mononitrate is not known.

Information for Patients

Patients should be told that the antianginal efficacy of Imdur Tablets can be maintained by carefully following the prescribed schedule of dosing. For most patients, this can be accomplished by taking the dose on arising.

As with other nitrates, daily headaches sometimes accompany treatment with isosorbide mononitrate. In patients who get these headaches, the headaches are a marker of the activity of the drug. Patients should resist the temptation to avoid headaches by altering the schedule of their treatment with isosorbide mononitrate, since loss of headache may be associated with simultaneous loss of antianginal efficacy. Aspirin or acetaminophen often successfully relieves isosorbide mononitrate-induced headaches with no deleterious effect on isosorbide mononitrate's antianginal efficacy.

Treatment with isosorbide mononitrate may be associated with light-headedness on standing, especially just after rising from a recumbent or seated position. This effect may be more frequent in patients who have also consumed alcohol.

Drug Interactions

The vasodilating effects of isosorbide mononitrate may be additive with those of other vasodilators. Alcohol, in particular, has been found to exhibit additive effects of this variety.

Marked symptomatic orthostatic hypotension has been reported when calcium channel blockers and organic nitrates were used in combination. Dose adjustments of either class of agents may be necessary.

Drug/Laboratory Test Interactions

Nitrates and nitrites may interfere with the Zlatkis-Zak color reaction, causing falsely low readings in serum cholesterol determinations.

Carcinogenesis, Mutagenesis, Impairment of Fertility

No evidence of carcinogenicity was observed in rats exposed to isosorbide mononitrate in their diets at doses of up to 900 mg/kg/day for the first 6 months and 500 mg/kg/day for the remaining duration of a study in which males were dosed for up to 121 weeks and females were dosed for up to 137 weeks. No evidence of carcinogenicity was observed in mice exposed to isosorbide mononitrate in their diets for up to 104 weeks at doses of up to 900 mg/kg/day.

Isosorbide mononitrate did not produce gene mutations (Ames test, mouse lymphoma test) or chromosome aberrations (human lymphocyte and mouse micronucleus tests) at biologically relevant concentrations.

No effects on fertility were observed in a study in which male and female rats were administered doses of up to 750 mg/kg/day beginning, in males, 9 weeks prior to mating, and in females, 2 weeks prior to mating.

Pregnancy

Teratogenic Effects

Pregnancy Category B

In studies designed to detect effects of isosorbide mononitrate on embryo-fetal development, doses of up to 240 or 248 mg/kg/day, administered to pregnant rats and rabbits, were unassociated with evidence of such effects. These animal doses are about 100 times the maximum recommended human dose (120 mg in a 50 kg woman) when comparison is based on body weight; when comparison is based on body surface area, the rat dose is about 17 times the human dose and the rabbit dose is about 38 times the human dose. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, Imdur Tablets should be used during pregnancy only if clearly needed.

Nonteratogenic Effects

Neonatal survival and development and incidence of stillbirths were adversely affected when pregnant rats were administered oral doses of 750 (but not 300) mg isosorbide mononitrate/kg/day during late gestation and lactation. This dose (about 312 times the human dose when comparison is based on body weight and 54 times the human dose when comparison is based on body surface area) was associated with decreases in maternal weight gain and motor activity and evidence of impaired lactation.

Nursing Mothers

It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when ISMN is administered to a nursing mother.

Pediatric Use

The safety and effectiveness of ISMN in pediatric patients have not been established.

Geriatric Use

Clinical studies of Imdur Tablets did not include sufficient information on patients age 65 and over to determine whether they respond differently from younger patients. Other reported clinical experience for Imdur has not identified differences in response between elderly and younger patients. Clinical experience for organic nitrates reported in the literature identified a potential for severe hypotension and increased sensitivity to nitrates in the elderly. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

Elderly patients may have reduced baroreceptor function and may develop severe orthostatic hypotension when vasodilators are used. Imdur should therefore be used with caution in elderly patients who may be volume depleted, on multiple medications or who, for whatever reason, are already hypotensive. Hypotension induced by isosorbide mononitrate may be accompanied by paradoxical bradycardia and increased angina pectoris.

Elderly patients may be more susceptible to hypotension and may be at a greater risk of falling at therapeutic doses of nitroglycerin.

Nitrate therapy may aggravate the angina caused by hypertrophic cardiomyopathy, particularly in the elderly.

You should not take erectile dysfunction medicine (Viagra, Cialis, Levitra, Stendra, Staxyn, sildenafil, avanafil, tadalafil, vardenafil) while you are taking Imdur. Taking these medicine together can cause a sudden and serious decrease in blood pressure.

Seek emergency medical attention if you have early symptoms of a heart attack (chest pain or pressure, pain spreading to your jaw or shoulder, sweating, general ill feeling).

Do not stop taking this medicine suddenly. Stopping suddenly could cause a severe angina attack.

Isosorbide mononitrate can cause severe headaches, especially when you first start using it. These headaches may gradually become less severe as you continue to use the medication. Do not stop taking Imdur. Ask your doctor before using any headache pain medication.

Use this medicine regularly to prevent an angina attack. Get your prescription refilled before you run out of medicine completely.

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Applies to isosorbide mononitrate: oral tablet, oral tablet extended release

General

The most common adverse effects are headache and dizziness.[Ref]

Nervous system

Very common (10% or more): Headache (up to 57%), dizziness (up to 11%)
Common (1% to 10%): Light-headedness
Frequency not reported: Bitter taste, paresthesia, impaired concentration, tremor, hypoesthesia, migraine, neuritis, paresis, somnolence, fainting, drowsiness
Postmarketing reports: Syncope[Ref]

Cardiovascular

Common (1% to 10%): Cardiovascular disorder, flushing, hypotension
Frequency not reported: Acute myocardial infarction, apoplexy, arrhythmias, bradycardia, edema, hypertension, pallor, palpitations, tachycardia, hot flushes, cardiac failure, arrhythmia, arrhythmia atrial, atrial fibrillation, bundle branch block, extrasystole, ventricular tachycardia, angina pectoris aggravated, heart murmur, heart sound abnormal, myocardial infarction, Q wave abnormality, intermittent claudication, varicose vein, reflex tachycardia, collapse, bradyarrhythmia, paroxysmal bradycardia, orthostatic hypotension[Ref]

Gastrointestinal

Common (1% to 10%): Nausea, abdominal pain, diarrhea, gastrointestinal disturbances
Frequency not reported: Dry mouth, dyspepsia, vomiting, constipation, flatulence, gastric ulcer, gastritis, glossitis, hemorrhagic gastric ulcer, hemorrhoids, loose stools, melena, heartburn[Ref]

Hypersensitivity

Common (1% to 10%): Allergic reaction[Ref]

Hematologic

Frequency not reported: Methemoglobinemia, thrombocytopenia, hypochromic anemia[Ref]

Other

Common (1% to 10%): Fatigue, pain, chest pain, tiredness
Frequency not reported: Susurrus aurium, vertigo, asthenia, fever, flu-like symptoms, malaise, rigors, earache, tinnitus, tympanic membrane perforation, breast pain, feeling of weakness[Ref]

Respiratory

Common (1% to 10%): Upper respiratory infection, increased cough
Frequency not reported: Asthma, dyspnea, sinusitis, bronchitis, bronchospasm, coughing, increased sputum, nasal congestion, pharyngitis, pneumonia, pulmonary infiltration, rales, rhinitis, hypoxia[Ref]

Dermatologic

Common (1% to 10%): Rash, pruritus
Frequency not reported: Sweating, purpura, acne, hair texture abnormal, increased sweating, skin nodule, leg ulcer, exfoliative dermatitis, excessive perspiration, allergic dermatitis, hyperhidrosis[Ref]

Psychiatric

Common (1% to 10%): Emotional lability, sleep disturbances
Frequency not reported: Anxiety, depression, insomnia, nervousness, nightmares, restlessness, confusion, decreased libido, paroniria[Ref]

Musculoskeletal

Very rare (less than 0.01%): Myalgia
Frequency not reported: Back pain, muscle cramps, neck pain, arthralgia, frozen shoulder, muscle weakness, musculoskeletal pain, myositis, tendon disorder, torticollis[Ref]

Metabolic

Frequency not reported: Anorexia, thirst, decreased weight, hyperuricemia, hypokalemia, poor appetite[Ref]

Genitourinary

Frequency not reported: Prostatic disorder, impotence, atrophic vaginitis, polyuria, urinary tract infection[Ref]

Ocular

Frequency not reported: Amblyopia, ptosis, conjunctivitis, photophobia, vision abnormal[Ref]

Immunologic

Frequency not reported: Bacterial infection, moniliasis, viral infection[Ref]

Hepatic

Frequency not reported: Serum glutamic oxaloacetic transaminase (SGOT) increased, serum glutamate-pyruvate transaminase (SGPT) increased[Ref]

Endocrine

Frequency not reported: Pituitary hemorrhage[Ref]

Renal

Frequency not reported: Renal calculus[Ref]

Some side effects of Imdur may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.