Generic

Isosorbide Mononitrate

Indications

Isosorbide mononitrate is used to prevent and treat angina pectoris caused by coronary artery disease. The speed of onset of oral isosorbide mononitrate is not high enough for the product to be used to stop acute angina attacks.

Pharmacology

Isosorbide mononitrate is the main active metabolite of isosorbide dinitrate (ISDN), and most of the clinical activity of isosorbide dinitrate can be attributed to mononitrate. The main pharmacological effect of isosorbide mononitrate is to relax vascular smooth muscle, and then expand peripheral arteries and veins, especially the latter. Vein dilation promotes the accumulation of peripheral blood and reduces venous return to the heart, thereby reducing left ventricular end-diastolic pressure and pulmonary capillary wedge pressure (preload). Arteriole relaxation can reduce systemic vascular resistance, systolic blood pressure, and mean arterial pressure (afterload). There is also dilation of the coronary arteries. The relative importance of reduced preload, reduced afterload, and coronary artery dilation has not yet been determined.

Dosage & Administration

Tablets: The usual oral dose is 1 tablet (20 mg) twice a day, to be taken first in the morning and then at 7 hour intervals. Although the maintenance dose ranges from 20 mg to 120 mg (16 tablets), a 10 mg (1/2 tablet) dose is appropriate when starting treatment with a lower dose or following the instructions of a registered physician.

Sustained Release Capsules: Usual oral dose is 1 capsule (50 mg) per day or follow the instructions of a registered physician.

Interaction

It is forbidden to use isosorbide mononitrate and any form of phosphodiesterase inhibitor at the same time.

The simultaneous use of isosorbide mononitrate and riociguat (a soluble guanylate cyclase stimulant) is contraindicated.

The vasodilator effects of isosorbide mononitrate can be combined with the effects of other vasodilators. In particular, it has been found that alcohol exhibits a cumulative effect of this variety.

When calcium channel blockers are used in combination with organic nitrates, obvious symptoms of orthostatic hypotension have been reported. Dose adjustments may be required for any type of medication.

Contraindications

Patients who are allergic to isosorbide mononitrate are contraindicated. Do not use isosorbide mononitrate, such as sildenafil, tadalafil, or vardenafil, in patients taking certain medications for erectile dysfunction (phosphodiesterase inhibitors). Simultaneous use may cause severe hypotension, syncope or myocardial ischemia. Do not use isosorbide mononitrate in patients taking riociguat, a soluble guanylate cyclase stimulant. Simultaneous use may cause hypotension.

Side Effects

Sometimes, headaches, dizziness, and low blood pressure can occur.

Pregnancy & Lactation

Pregnancy Category B: Reproduction studies performed in rats and rabbits at doses up to 540 and 810 mg / kg / day, respectively, showed no evidence that isosorbide mononitrate caused harm to the fetus. However, there are no adequate and well-controlled studies in pregnant women. Because animal reproduction studies do not always predict human response, isosorbide mononitrate should be used during pregnancy only when clearly necessary.

Precautions & Warnings

Even with small doses of isosorbide mononitrate, severe hypotension can occur, especially in an upright posture. Therefore, the drug should be used with caution in patients who may have insufficient capacity or who have developed hypotension for some reason. Hypotension caused by isosorbide mononitrate can be accompanied by paradoxical bradycardia and exacerbation of angina pectoris.

Nitrate therapy can aggravate angina pectoris caused by hypertrophic cardiomyopathy. In industrial workers who have been exposed to unknown (possibly high) doses of organic nitrates for a long time, tolerance clearly occurs. These workers suffered chest pain, acute myocardial infarction, and even sudden death during the temporary stop of nitrate, which proved the existence of real physical dependence. The significance of these observations for the routine clinical use of oral isosorbide mononitrate is unclear.

Patients should be informed that the anti-angina efficacy of isosorbide mononitrate tablets can be maintained by carefully following the prescribed dosing schedule (two doses seven hours apart). For most patients, this can be achieved by taking the first dose when waking up and taking the second dose 7 hours later.

Like other nitrates, treatment with isosorbide mononitrate is sometimes accompanied by daily headaches. In patients suffering from these headaches, the headache is a sign of drug activity. Patients must resist the temptation to use isosorbide mononitrate to change the treatment regimen to avoid headaches, because the disappearance of headaches may be related to the loss of anti-angina efficacy at the same time. On the other hand, aspirin and/or acetaminophen can usually successfully relieve headaches caused by isosorbide mononitrate without any harmful effects on the antiangina efficacy of isosorbide mononitrate.

Treatment with isosorbide mononitrate may be related to dizziness while standing, especially just after getting up from a reclining or sitting position. This effect may be more common in patients who also drink alcohol.

Therapeutic Class

Nitrates: Coronary vasodilators

Storage Conditions

Store at 20-30° C.

Pharmaceutical Name

Drug International Ltd.