DailyMed Label: Isosorbide Dinitrate

DailyMed Label: Isosorbide

2010

DailyMed Prescription

Isosorbide

ISOSORBIDE DINITRATE

State of Florida DOH Central Pharmacy

NDC: 53808-0274

NDC: 53808-0274

NDC: 53808-0275

NDC: 53808-0275

Isosorbide dinitrate (ISDN) 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. ISDN 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). ISDN is freely soluble in organic solvents such as acetone, alcohol, and ether, but is only sparingly soluble in water. Each isosorbide dinitrate tablet contains 5 mg, 10 mg, or 20 mg of ISDN. Inactive ingredients are as follows: 5 mg and 10 mg: Ammonium phosphate dibasic, anhydrous lactose, magnesium stearate, microcrystalline cellulose, sodium starch glycolate. 20 mg: Ammonium phosphate dibasic, anhydrous lactose, D&C Yellow No. 10 Lake. FD&C Blue No. 1 Lake, FD&C Yellow No. 6 Lake, magnesium stearate, microcrystalline cellulose, sodium starch glycolate. Structural Formula

Isosorbide dinitrate oral tablets are indicated for the prevention of angina pectoris due to coronary artery disease. The onset of action of immediate-release oral ISDN is not sufficiently rapid for this product to be useful in aborting an acute anginal episode.

As noted under CLINICAL PHARMACOLOGY , multiple 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 oral 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. As also noted under CLINICAL PHARMACOLOGY , the effects of the second and later doses have been smaller and shorter-lasting than the effects of the first. Large controlled studies with other nitrates suggest that no dosing regimen with isosorbide dinitrate oral tablets should be expected to provide more than about 12 hours of continuous anti-anginal efficacy per day. As with all titratable drugs, it is important to administer the minimum dose which produces the desired clinical effect. The usual starting dose of isosorbide dinitrate oral tablets is 5 mg to 20 mg, two or three times daily. For maintenance therapy, 10 mg to 40 mg, two or three times daily is recommended. Some patients may require higher doses. A daily dose-free interval of at least 14 hours is advisable to minimize tolerance. The optimal interval will vary with the individual patient, dose and regimen.

Allergic reactions to organic nitrates are extremely rare, but they do occur. The isosorbide dinitrate tablet is contraindicated in patients who are allergic to ISDN or any of its other ingredients.

General: Severe hypotension, particularly with upright posture, may occur with even small doses of ISDN. 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 ISDN may be accompanied by paradoxical bradycardia and increased angina pectoris. Nitrate therapy may aggravate the angina caused by hypertrophic cardiomyopathy. As tolerance to ISDN develops, the effect of sublingual nitroglycerin on exercise tolerance, although still observable, is somewhat blunted. Some clinical trials in angina patients have provided nitroglycerin for about 12 continuous hours of every 24-hour day. During the daily dose-free interval in some of these trials, anginal attacks have been more easily provoked than before treatment, and patients have demonstrated hemodynamic rebound and decreased exercise tolerance. The importance of these observations to the routine, clinical use of sublingual and immediate-release oral ISDN is not known. 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. Information for Patients: Patients should be told that the anti-anginal efficacy of ISDN is strongly related to its dosing regimen, so the prescribed schedule of dosing should be followed carefully. In particular, daily headaches sometimes accompany treatment with ISDN. 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 ISDN, since loss of headache may be associated with simultaneous loss of anti-anginal efficacy. Aspirin and/or acetaminophen, on the other hand, often successfully relieve ISDN-induced headaches with no deleterious effect on ISDN'S anti-anginal efficacy. Treatment with ISDN may be associated with lightheadedness 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 ISDN may be additive with those of other vasodilators. Alcohol, in particular, has been found to exhibit additive effects of this variety. Carcinogenesis. Mutagenesis. Impairment of Fertility: No long-term studies in animals have been performed to evaluate the carcinogenic potential of ISDN. In a modified two-litter reproduction study, there was no remarkable gross pathology and no altered fertility or gestation among rats fed ISDN at 25 or 100 mg/kg/day. Pregnancy Category C: At oral doses 35 and 150 times the maximum recommended human daily dose. ISDN has been shown to cause a dose-related increase in embryotoxicity (increase in mummified pups) in rabbits. There are no adequate, well-controlled studies in pregnant women. ISDN should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Nursing Mothers: It is not known whether ISDN is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when ISDN is administered to a nursing woman. Pediatric Use: Safety and effectiveness in pediatric patients have not been established. Geriatric Use: Clinical studies of ISDN did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. 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.

Adverse reactions to ISDN are generally dose-related, and most all of these reactions are the result of ISDN'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.

Drug Interactions: The vasodilating effects of ISDN may be additive with those of other vasodilators. Alcohol, in particular, has been found to exhibit additive effects of this variety.

Isosorbide Dinitrate Tablets USP (Oral) 5 mg: White, round, scored tablets imprinted "West-ward 769". Isosorbide Dinitrate Tablets USP (Oral) 10 mg: White, round, scored tablets imprinted "WW" on one side and "771" on the other side. Isosorbide Dinitrate Tablets USP (Oral) 20 mg: Green, round, scored tablet imprinted "WW" on one side and "772" on the other side. They are supplied by State of Florida DOH Central Pharmacy as follows: NDC Strength Quantity/Form Color Source Prod. Code 53808-0274-1 10 mg 30 Tablets in a Blister Pack WHITE 0143-1771 53808-0275-1 20 mg 30 Tablets in a Blister Pack GREEN 0143-1772 Dispense in a tight, light-resistant container as defined in the USP using a child-resistant closure. Store at 20-25°C (68-77°F) [See USP Controlled Room Temperature]. Protect from light and moisture. Also available: Isosorbide Dinitrate Sublingual Tablets in the following dosage strengths: 2.5 mg; in bottles of 100, 1000 or unit dose boxes of 100 tablets. 5 mg; in bottles of 100, 1000 or unit dose boxes of 100 tablets. Manufactured by: West-ward Pharmaceutical Corp. Eatontown, NJ 07724 This Product was Repackaged By: State of Florida DOH Central Pharmacy 104-2 Hamilton Park Drive Tallahassee, FL 32304 United States

The principal pharmacological action of ISDN 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 lesistance, 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. Pharmacokinetics: Absorption of ISDN after oral dosing is nearly complete, but bioavailability is highly variable (10% to 90%), with extensive first-pass metabolism in the liver. Serum levels reach their maxima about an hour after ingestion. The average bioavailability of ISDN is about 25%; most studies have observed progressive increases in bioavailability during chronic therapy. Once absorbed, the distribution volume of ISDN is 2 to 4 L/kg, and this volume is cleared at the rate of 2 to 4 L/min, so ISDN's half-life in serum is about an hour. Since the clearance exceeds hepatic blood flow, considerable extrahepatic metabolism must also occur. Clearance is affected primarily by denitration to the 2-mononitrate (15 to 25%) and the 5-mononitrate (75 to 85%). Both metabolites have biological activity, especially the 5-mononitrate. With an overall half-life of about 5 hours, the 5-mononitrate is cleared from the serum by denitration to isosorbide; glucuronidation to the 5-mononitrate glucuronide; and denitration/hydration to sorbitol. The 2-mononitrate has been less well studied, but it appears to participate in the same metabolic pathways, with a half-life of about 2 hours. The daily dose-free interval sufficient to avoid tolerance to organic nitrates has not been well defined. Studies of nitroglycerin (an organic nitrate with a very short half-life) have shown that daily dose-free intervals of 10 to 12 hours are usually sufficient to minimize tolerance. Daily dose-free intervals that have succeeded in avoiding tolerance during trials of moderate doses ( e.g., 30 mg) of immediate-release ISDN have generally been somewhat longer (at least 14 hours), but this is consistent with the longer half-lives of ISDN and its active metabolites. Few well-controlled clinical trials of organic nitrates have been designed to detect rebound or withdrawal effects. In one such trial, however, subjects receiving nitroglycerin had less exercise tolerance at the end of the daily dose-fiee interval than the parallel group receiving placebo. The incidence, magnitude, and clinical significance of similar phenomena in patients receiving ISDN have not been studied. Clinical trials: In clinical trials, immediate-release oral ISDN has been administered in a variety of regimens, with total daily doses ranging from 30 mg to 480 mg. Controlled trials of single oral doses of ISDN have demonstrated effective reductions in exercise-related angina for up to 8 hours. Anti-anginal activity is present about 1 hour after dosing. Most controlled trials of multiple-dose oral ISDN taken every 12 hours (or more frequently) for several weeks have shown statistically significant anti-anginal efficacy for only 2 hours after dosing. Once-daily regimens, and regimens with one daily dose-free interval of at least 14 hours ( e.g., a regimen providing doses at 0800, 1400, and 1800 hours'), have shown efficacy after the first dose of each day that was similar to that shown in the single-dose studies cited above. The effects of the second and later doses have been smaller and shorter-lasting than the effect of the first. From large, well-controlled studies of other nitrates, it is reasonable to believe that the maximal achievable daily duration of anti-anginal effect from ISDN is about 12 hours. No dosing regimen for ISDN has, however, ever actually been shown to achieve this duration of effect. One study of 8 patients administered a pretitrated dose (average 27.5 mg) of immediate-release ISDN at 0800, 1300, and 1800 hours for 2 weeks, revealed that significant anti-anginal effectiveness was discontinuous and totaled about 6 hours in a 24 hour period.

Label image for 10mg