Isosorbide Mononitrate

INDICATIONS AND USAGE Isosorbide mononitrate extended-release tablets, USP 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.

DOSAGE & ADMINISTRATION The recommended starting dose of Isosorbide Mononitrate Extended-Release Tablets, USP is 30 mg (given as a single 30 mg tablet or as 1/2 of a 60 mg tablet) or 60 mg (given as a single tablet) once daily. After several days, the dosage may be increased to 120 mg (given as a single 120 mg tablet or as two 60 mg tablets) once daily. Rarely, 240 mg may be required. The daily dose of Isosorbide Mononitrate Extended-Release Tablets, USP should be taken in the morning on arising. Isosorbide Mononitrate Extended-Release Tablets, USP should not be chewed or crushed and should be swallowed together with a half-glassful of fluid. Do not break the 30 mg tablet.

CONTRAINDICATIONS Isosorbide mononitrate extended-release tablets are contraindicated in patients who have shown hypersensitivity or idiosyncratic reactions to other nitrates or nitrites.

ADVERSE REACTIONS The table below shows the frequencies of the adverse events that occurred in >5% of the subjects in three placebo-controlled North American studies in which patients in the active treatment arm received 30 mg, 60 mg, 120 mg, or 240 mg of isosorbide mononitrate extended-release tablets once daily. In parentheses, the same table shows the frequencies with which these adverse events were associated with the discontinuation of treatment. Overall, 8% of the patients who received 30 mg, 60 mg, 120 mg, or 240 mg of isosorbide mononitrate in the three placebo-controlled North American studies discontinued treatment because of adverse events. Most of these discontinued because of headache. Dizziness was rarely associated with withdrawal from these studies. Since headache appears to be a dose-related adverse effect and tends to disappear with continued treatment, it is recommended that isosorbide mononitrate extended-release tablets treatment be initiated at low doses for several days before being increased to desired levels. FREQUENCY AND ADVERSE EVENTS (DISCONTINUED) a Three Controlled North American Studies Dose Placebo 30 mg 60 mg 120 mg* 240 mg* Patients 96 60 102 65 65 Headache 15% (0%) 38% (5%) 51% (8%) 42% (5%) 57% (8%) Dizziness 4% (0%) 8% (0%) 11% (1%) 9% (2%) 9% (2%) a Some individuals discontinued for multiple reasons. * Patients were started on 60 mg and titrated to their final dose. In addition, the three North American trials were pooled with 11 controlled trials conducted in Europe. Among the 14 controlled trials, a total of 711 patients were randomized to isosorbide mononitrate extended-release tablets. When the pooled data were reviewed, headache and dizziness were the only adverse events that were reported by >5% of patients. Other adverse events, each reported by ≤5% of exposed patients, and in many cases of uncertain relation to drug treatment, were: Autonomic Nervous System Disorders : Dry mouth, hot flushes. Body as a Whole : Asthenia, back pain, chest pain, edema, fatigue, fever, flu-like symptoms, malaise, rigors. Cardiovascular Disorders, General : Cardiac failure, hypertension, hypotension. Central and Peripheral Nervous System Disorders : Dizziness, headache, hypoesthesia, migraine, neuritis, paresis, paresthesia, ptosis, tremor, vertigo. Gastrointestinal System Disorders : Abdominal pain, constipation, diarrhea, dyspepsia, flatulence, gastric ulcer, gastritis, glossitis, hemorrhagic gastric ulcer, hemorrhoids, loose stools, melena, nausea, vomiting. Hearing and Vestibular Disorders : Earache, tinnitus, tympanic membrane perforation. Heart Rate and Rhythm Disorders : Arrhythmia, arrhythmia atrial, atrial fibrillation, bradycardia, bundle branch block, extrasystole, palpitation, tachycardia, ventricular tachycardia. Liver and Biliary System Disorders : SGOT increase, SGPT increase. Metabolic and Nutritional Disorders : Hyperuricemia, hypokalemia. Musculoskeletal System Disorders : Arthralgia, frozen shoulder, muscle weakness, musculoskeletal pain, myalgia, myositis, tendon disorder, torticollis. Myo-, Endo-, Pericardial and Valve Disorders : Angina pectoris aggravated, heart murmur, heart sound abnormal, myocardial infarction, Q wave abnormality. Platelet, Bleeding and Clotting Disorders : Purpura, thrombocytopenia. Psychiatric Disorders : Anxiety, concentration impaired, confusion, decreased libido, depression, impotence, insomnia, nervousness, paroniria, somnolence. Red Blood Cell Disorder : Hypochromic anemia. Reproductive Disorders, Female : Atrophic vaginitis, breast pain. Resistance Mechanism Disorders : Bacterial infection, moniliasis, viral infection. Respiratory System Disorders : Bronchitis, bronchospasm, coughing, dyspnea, increased sputum, nasal congestion, pharyngitis, pneumonia, pulmonary infiltration, rales, rhinitis, sinusitis. Skin and Appendages Disorders : Acne, hair texture abnormal, increased sweating, pruritus, rash, skin nodule. Urinary System Disorders : Polyuria, rena …

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.

Mechanism of Action Isosorbide mononitrate extended-release tablet are an oral extended-release formulation of ISMN, the major active metabolite of isosorbide dinitrate; most of the clinical activity of the dinitrate is attributable to the mononitrate. The principal pharmacological action of ISMN and all organic nitrates in general is relaxation of vascular smooth muscle, producing dilatation of peripheral arteries and veins, especially the latter. Dilatation of the veins promotes peripheral pooling of blood and decreases venous return to the heart, thereby reducing left ventricular end-diastolic pressure and pulmonary capillary wedge pressure (preload). Arteriolar relaxation reduces systemic vascular resistance, systolic arterial pressure and mean arterial pressure (afterload). Dilatation of the coronary arteries also occurs. The relative importance of preload reduction, afterload reduction, and coronary dilatation remains undefined.

DESCRIPTION Isosorbide mononitrate (ISMN), an organic nitrate and the major biologically active metabolite of isosorbide dinitrate (ISDN), is a vasodilator with effects on both arteries and veins. Isosorbide mononitrate tablets contain either 30 mg, 60 mg or 120 mg of isosorbide mononitrate in an extended-release formulation. In addition, ISMN 30 mg tablets, USP contains the following inactive ingredients: colloidal silicon dioxide, compressible sugar, hydroxypropyl methylcellulose, lactose monohydrate, magnesium stearate. ISMN 60 mg tablets, USP contains the following inactive ingredients: colloidal silicon dioxide, compressible sugar, hydroxypropyl methylcellulose, lactose monohydrate, magnesium stearate, yellow iron oxide. ISMN 120 mg tablets, USP contains the following inactive ingredients: colloidal silicon dioxide, hydroxypropyl cellulose, hypromellose, lactose monohydrate, magnesium stearate and talc. The molecular formula of ISMN is C 6 H 9 NO 6 and the molecular weight is 191.14. The chemical name for ISMN is 1,4:3,6-dianhydro-,D-glucitol 5-nitrate; the compound has the following structural formula: ISMN is a white, crystalline, odorless compound which is stable in air and in solution, has a melting point of about 90°C, and an optical rotation of +140° to 146° (2% in water, 20°C). Isosorbide mononitrate is freely soluble in water, acetic acid, alcohol, acetone and ethyl acetate; soluble in ether and chloroform, slightly soluble in toluene; practically insoluble in aliphatic hydrocarbons. Isosorbide mononitrate extended-release 120 mg tablets, USP meets USP Dissolution Test 7. Isosorbide mononitrate extended-release 30 mg and 60 mg tablets, USP meets USP Dissolution Test 5. structure

OVERDOSAGE Hemodynamic Effects The ill effects of isosorbide mononitrate overdose are generally the result of isosorbide mononitrate's capacity to induce vasodilatation, venous pooling, reduced cardiac output, and hypotension. These hemodynamic changes may have protean manifestations, including increased intracranial pressure, with any or all of persistent throbbing headache, confusion, and moderate fever; vertigo, palpitations; visual disturbances; nausea and vomiting (possibly with colic and even bloody diarrhea); syncope (especially in the upright posture); air hunger and dyspnea, later followed by reduced ventilatory effort; diaphoresis, with the skin either flushed or cold and clammy; heart block and bradycardia; paralysis; coma; seizures and death. Laboratory determinations of serum levels of isosorbide mononitrate and its metabolites are not widely available, and such determinations have, in any event, no established role in the management of isosorbide mononitrate overdose. There are no data suggesting what dose of isosorbide mononitrate is likely to be life threatening in humans. In rats and mice, there is significant lethality at doses of 2000 mg/kg and 3000 mg/kg, respectively. No data are available to suggest physiological maneuvers (eg, maneuvers to change the pH of the urine) that might accelerate elimination of isosorbide mononitrate. In particular, dialysis is known to be ineffective in removing isosorbide mononitrate from the body. No specific antagonist to the vasodilator effects of isosorbide mononitrate is known, and no intervention has been subject to controlled study as a therapy of isosorbide mononitrate overdose. Because the hypotension associated with isosorbide mononitrate overdose is the result of venodilatation and arterial hypovolemia, prudent therapy in this situation should be directed toward an increase in central fluid volume. Passive elevation of the patient's legs may be sufficient, but intravenous infusion of normal saline or similar fluid may also be necessary. The use of epinephrine or other arterial vasoconstrictors in this setting is likely to do more harm than good. In patients with renal disease or congestive heart failure, therapy resulting in central volume expansion is not without hazard. Treatment of isosorbide mononitrate overdose in these patients may be subtle and difficult, and invasive monitoring may be required. Methemoglobinemia Methemoglobinemia has been reported in patients receiving other organic nitrates, and it probably could also occur as a side effect of isosorbide mononitrate. Certainly nitrate ions liberated during metabolism of isosorbide mononitrate can oxidize hemoglobin into methemoglobin. Even in patients totally without cytochrome b 5 reductase activity, however, and even assuming that the nitrate moiety of isosorbide mononitrate is quantitatively applied to oxidation of hemoglobin, about 2 mg/kg of isosorbide mononitrate should be required before any of these patients manifest clinically significant (≥10%) methemoglobinemia. In patients with normal reductase function, significant production of methemoglobin should require even larger doses of isosorbide mononitrate. In one study in which 36 patients received 2 to 4 weeks of continuous nitroglycerin therapy at 3.1 to 4.4 mg/hr (equivalent, in total administered dose of nitrate ions, to 7.8 to 11.1 mg of isosorbide mononitrate per hour), the average methemoglobin level measured was 0.2%; this was comparable to that observed in parallel patients who received placebo. Not with standing these observations, there are case reports of significant methemoglobinemia in association with moderate overdoses of organic nitrates. None of the affected patients had been thought to be unusually susceptible. Methemoglobin levels are available from most clinical laboratories. The diagnosis should be suspected in patients who exhibit signs of impaired oxygen delivery despite adequate cardiac output and adequate arterial pO 2 . Cl …

HOW SUPPLIED Isosorbide mononitrate extended-release tablets, USP 30 mg are white to off-white, oval shaped, film coated tablets having breakline on one side and debossed ‘3-0’ across breakline and ‘1104’ on other side. They are supplied as follows: Cartons of 100 film-coated extended-release tablets (10 film-coated extended-release tablets each blister pack x 10), NDC 0904-6449-61 Isosorbide mononitrate extended-release tablets, USP 60 mg are white to off-white, oval shaped, film coated tablets having breakline on one side and ‘60-60’ debossing across breakline and ‘1105’ on the other side. Cartons of 100 film-coated extended-release tablets (10 film-coated extended-release tablets each blister pack x 10), NDC 0904-6450-61 WARNING: These Unit Dose packages are not child resistant and are Intended for Institutional Use Only. Keep this and all drugs out of the reach of children. Store at 20°-25°C (68°-77°F), excursions permitted to 15°-30°C (59°-86°F) [see USP Controlled Room Temperature] Manufactured by: Torrent Pharmaceuticals LTD., India. Manufactured for: Torrent Pharma INC., Basking Ridge, NJ 07920. Packaged and Distributed by: MAJOR® PHARMACEUTICALS Indianapolis, IN 46268 USA Refer to package label for Distributor's NDC Number 8109641 Revised: April 2026 logo