displayName: DESCRIPTION SECTION
FDA Article Code: 34089-3
Isosorbide dinitrate (ISDN), an organic nitrate, is a vasodilator with effects on both arteries and veins. Isosorbide dinitrate is available as 40 mg extended-release tablets. The chemical name for isosorbide dinitrate is 1,4:3,6–dianhydro–D–glucitol 2, 5-dinitrate, an organic nitrate whose structural formula is and whose molecular weight is 236.14. The organic nitrates are vasodilators, active on both arteries and veins.Isosorbide dinitrate is a white, crystalline, odorless compound which is stable in air and in solution, has a melting point of 70°C and has an optical rotation of +134° (c=1.0, alcohol, 20°C). Isosorbide dinitrate is freely soluble in organic solvents, such as acetone, alcohol, and ether, but is only sparingly soluble in water.Each Isosorbide Dinitrate Extended-release tablet, for oral administration, contains 40 mg of isosorbide dinitrate, in a matrix that causes the active drug to be released over a sustained period. In addition, each tablet also contains the following inactive ingredients: anhydrous lactose, colloidal silicon dioxide, FD&C Yellow #6 Aluminum Lake, hydroxypropyl methylcellulose, magnesium stearate, and stearic acid.Conformance of Isosorbide Dinitrate Extended-release Tablets with the USP release test is pending.
displayName: CLINICAL PHARMACOLOGY SECTION
FDA Article Code: 34090-1
The principal pharmacological action of isosorbide dinitrate is relaxation of vascular smooth muscle and consequent 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.Dosing regimens for most chronically used drugs are designed to provide plasma concentrations that are continuously greater than a minimally effective concentration. This strategy is inappropriate for organic nitrates. Several well-controlled clinical trials have used exercise testing to assess the anti-anginal efficacy of continuously-delivered nitrates. In the large majority of these trials, active agents were no more effective than placebo after 24 hours (or less) of continuous therapy. Attempts to overcome nitrate tolerance by dose escalation, even to doses far in excess of those used acutely, have consistently failed. Only after nitrates have been absent from the body for several hours has their anti-anginal efficacy been restored.
INDICATIONS AND USAGE
displayName: INDICATIONS & USAGE SECTION
FDA Article Code: 34067-9
Isosorbide Dinitrate Extended-release Tablets are indicated for the prevention of angina pectoris due to coronary artery disease. The onset of action of controlled-release oral isosorbide dinitrate is not sufficiently rapid for this product to be useful in aborting an acute anginal episode.
displayName: CONTRAINDICATIONS SECTION
FDA Article Code: 34070-3
Allergic reactions to organic nitrates are extremely rare, but they do occur. Isosorbide Dinitrate Extended-release Tablets are contraindicated in patients who are allergic to isosorbide dinitrate or to any of its other ingredients.
displayName: WARNINGS SECTION
FDA Article Code: 34071-1
Amplification of the vasodilatory effects of isosorbide dinitrate by sildenafil can result in severe hypotension. The time course and dose dependence of this interaction have not been studied. Appropriate supportive care has not been studied, but it seems reasonable to treat this as nitrate overdose, with elevation of the extremities and with central volume expansion.The benefits of controlled-release oral isosorbide dinitrate in patients with acute myocardial infarction or congestive heart failure have not been established. If one elects to use isosorbide dinitrate in these conditions, careful clinical or hemodynamic monitoring must be used to avoid the hazards of hypotension and tachycardia. Because the effects of controlled-release oral isosorbide dinitrate are so difficult to terminate rapidly, this formulation is not recommended in these settings.
displayName: ADVERSE REACTIONS SECTION
FDA Article Code: 34084-4
Adverse reactions to isosorbide dinitrate are generally dose-related, and almost all of these reactions are the result of isosorbide dinitrate’s activity as a vasodilator. Headache, which may be severe, is the most commonly reported side effect. Headache may be recurrent with each daily dose, especially at higher doses. Transient episodes of lightheadedness, occasionally related to blood pressure changes, may also occur. Hypotension occurs infrequently, but in some patients it may be severe enough to warrant discontinuation of therapy. Syncope, crescendo angina, and rebound hypertension have been reported but are uncommon.Extremely rarely, ordinary doses of organic nitrates have caused methemoglobinemia in normal-seeming patients. Methemoglobinemia is so infrequent at these doses that further discussion of its diagnosis and treatment is deferred (see “OVERDOSAGE”).Data are not available to allow estimation of the frequency of adverse reactions during treatment with Isosorbide Dinitrate Extended-release Tablets.
DOSAGE AND ADMINISTRATION
displayName: DOSAGE & ADMINISTRATION SECTION
FDA Article Code: 34068-7
As noted under “CLINICAL PHARMACOLOGY” multiple-dose studies with ISDN and other nitrates have shown that maintenance of continuous 24-hour plasma levels results in refractory tolerance. Every dosing regimen for Isosorbide Dinitrate Extended-release Tablets must provide a daily dose-free interval to minimize the development of this tolerance. With immediate-release ISDN, it appears that one daily dose-free interval must be at least 14 hours long. The necessary dose-free interval for Isosorbide Dinitrate Extended-release Tablets has not been clearly identified, but is presumably somewhat longer.As also noted under “CLINICAL PHARMACOLOGY” only one trial has ever studied the use of controlled-release isosorbide dinitrate for more than one dose. In that trial, 40 mg of a different formulation of controlled-release ISDN was administered twice daily in doses given 6 hours apart. After 4 weeks, active treatment could not be distinguished from placebo.Large controlled studies with other nitrates suggest that no dosing regimen with Isosorbide Dinitrate Extended-release Tablets should be expected to provide more than about 12 hours of continuous anti-anginal efficacy per day.In clinical trials, immediate-release oral isosorbide dinitrate has been administered in a variety of regimens, with total daily doses ranging from 30 mg to 480 mg.
displayName: HOW SUPPLIED SECTION
FDA Article Code: 34069-5
Isosorbide Dinitrate Extended–release Tablets, USP 40 mg are available as round, scored, peach colored tablets, debossed IL/3613, in bottles of 100 (NDC 0258–3613–01) and 1000 (NDC 0258–3613–10).
displayName: STORAGE AND HANDLING SECTION
FDA Article Code: 44425-7
Store at controlled room temperature 15°–30°C (59°–86°F). Dispense in well closed container.Inwood Laboratories, Inc.
Inwood, NY 11096
Subsidiary of Forest Laboratories, Inc.
Revised February 2002
©2002 Forest Laboratories, Inc.MG #7498