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.

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 Isordil® Titradose® tablet contains 5 mg or 40 mg of isosorbide dinitrate. The inactive ingredients in 5 mg tablet are magnesium stearate, lactose monohydrate, microcrystalline cellulose and FD&C red 40. The inactive ingredients in 40 mg tablet are magnesium stearate, microcrystalline cellulose, FD&C yellow 6, D&C yellow 10, and FD&C blue.

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.

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

Isordil Titradose is contraindicated in patients who are allergic to isosorbide dinitrate or any of its ingredients.

Do not use Isordil Titradose in patients who are taking certain drugs for erectile dysfunction (phosphodiesterase inhibitors), such as sildenafil, tadalafil, or vardenafil. Concomitant use can cause severe hypotension, syncope, or myocardial ischemia.

Do not use Isordil Titradose in patients who are taking the soluble guanylate cyclase stimulator riociguat. Concomitant use can cause hypotension.

The benefits of immediate-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 oral isosorbide dinitrate are so difficult to terminate rapidly, this formulation is not recommended in these settings.

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

Data are not available to allow estimation of the frequency of adverse reactions during treatment with Isordil Titradose tablets.

As noted under

As also noted under

Large controlled studies with other nitrates suggest that no dosing regimen with Isordil Titradose 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 Isordil Titradose 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.

IsordilTitradose (isosorbide dinitrate) tablets are available as follows:

5 mg, round, pink tablets imprinted "BPI 152" on one side and deeply scored on reverse side:

NDC 0187-0152-01, bottles of 100.

40 mg, round, light green tablets imprinted "BPI 192" on one side and deeply scored on reverse side:

NDC 0187-0192-01, bottles of 100.

Store at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature].

Protect from light.

Keep bottles tightly closed.

Dispense in a light-resistant, tight container.

®/™ are trademarks of Bausch Health Companies Inc. or its affiliates.

© 2019 Bausch Health Companies Inc. or its affiliates

9651602 20002689

Rev. 08/2019

Contains FD&C Yellow No. 6 as a color additive.