Isomon - General Information
Isosorbide mononitrate is a drug used principally in the treatment of angina pectoris and acts by dilating the blood vessels so as to reduce the blood pressure. It is sold by AstraZeneca under the trade name Imdur.
Isosorbide mononitrate is used to for the the prophylactic treatment of angina pectoris; that is, it is taken in order to prevent or at least reduce the occurrence of angina. Research on Isosorbide mononitrate as a cervical ripener to reduce time at hospital to birth is supportive.
Isosorbide mononitrate is an active metabolite of isosorbide dinitrate and exerts qualitatively similar effects. Isosorbide mononitrate reduces the workload of the heart by producing venous and arterial dilation. By reducing the end diastolic pressure and volume, isosorbide mononitrate lowers intramural pressure, hence leading to an improvement in the subendocardial blood flow. The net effect when administering isosorbide mononitrate is therefore a reduced workload for the heart and an improvement in the oxygen supply/demand balance of the myocardium.
The adverse reactions which follow have been reported in studies with isosorbide mononitrate:
Very common. Headache predominates (up to 30%) necessitating withdrawal of 2 to 3 % of patients, but the incidence reduces rapidly as treatment continues .
Common. Tiredness, sleep disturbances (6%) and gastrointestinal disturbances (6%) have been reported during clinical trials with isosorbide mononitrate modified release tablets, but at a frequency no greater than for placebo. Hypotension (4 to 5%), poor appetite (2.5%), nausea (1%).
Adverse effects associated with the clinical use of the drug are as expected with all nitrate preparations. They occur mainly in the early stages of treatment.
Hypotension (4%) with symptoms such as dizziness and nausea (1%) have been reported. These symptoms generally disappear during long-term treatment.
Other reactions that have been reported with isosorbide mononitrate modified release tablets include tachycardia, vomiting, diarrhoea, vertigo and heartburn
Pharmacology of Isomon
Isosorbide-5-mononitrate, the long-acting metabolite of isosorbide dinitrate, is used as a vasodilatory agent in the management of angina pectoris. By dilating the vessels, it lowers the blood pressure and reduces the left ventricular preload and afterload, therefore, leads to a reduction of myocardial oxygen requirement.
Isomon for patients
Isosorbide mononitrate is used to prevent chest pain in patients with a heart condition known as angina. This medication is normally taken twice a day. The first dose should be taken in the morning and second dose should be taken 7 hours later. This medication works by dilating blood vessels throughout the body. This can cause dizziness and lightheadedness when standing quickly and during the first days of therapy. This medication can cause headache - which also indicates the drug is working. These headaches are relieved with aspirin or acetaminophen. For this drug to be most effective it should be taken as prescribed, separating doses by 7 hours. Missed doses should not be doubled up.
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.
Immediate Release Tablets: Allergic reactions to organic nitrates are extremely rare, but they do occur. Isosorbide mononitrate is contraindicated in patients who are allergic to it.
Extended Release Tablets: Isosorbide mononitrate extended release tablets are contraindicated in patients who have shown hypersensitivity or idiosyncratic reactions to other nitrates or nitrites.
Additional information about Isomon
Isomon Indication: For the prevention of angina pectoris due to coronary artery disease and the treatment of acute and chronic angina pectoris, hypertension, and myocardial infarction.
Mechanism Of Action: Similar to other nitrites and organic nitrates, Isomon is converted to nitric oxide (NO), an active intermediate compound which activates the enzyme guanylate cyclase (Atrial natriuretic peptide receptor A). This stimulates the synthesis of cyclic guanosine 3',5'-monophosphate (cGMP) which then activates a series of protein kinase-dependent phosphorylations in the smooth muscle cells, eventually resulting in the dephosphorylation of the myosin light chain of the smooth muscle fiber. The subsequent release of calcium ions results in the relaxation of the smooth muscle cells and vasodilation.
Drug Interactions: Dihydroergotamine Possible antagonism of action
Dihydroergotoxine Possible antagonism of action
Ergonovine Possible antagonism of action
Ergotamine Possible antagonism of action
Methylergonovine Possible antagonism of action
Methysergide Possible antagonism of action
Vardenafil Possible significant hypotension with this combination
Tadalafil Possible significant hypotension with this combination
Sildenafil Possible significant hypotension with this combination
Food Interactions: Take without regard to meals.
Generic Name: Isosorbide Mononitrate
Synonyms: Isosorbidi Mononitras [Latin]; Mononitrate d'Isosorbide [French]; Mononitrato de Isosorbida [Spanish]; Monosorbitrate; IHD; ISMN
Drug Category: Vasodilator Agents; Nitrates and Nitrites; Nitric Oxide Donors
Drug Type: Small Molecule; Approved
Toxicity (Overdose): Symptoms of overdose include vasodilatation, venous pooling, reduced cardiac output, and hypotension. 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.
Protein Binding: 5%
Half Life: 5 hours
Dosage Forms of Isomon: Tablet, extended release Oral
Chemical IUPAC Name: [(3R,3aS,6S,6aR)-6-hydroxy-2,3,3a,5,6,6a-hexahydrofuro[2,3-d]furan-3-yl] nitrate
Chemical Formula: C6H9NO6
Isosorbide Mononitrate on Wikipedia: https://en.wikipedia.org/wiki/Isosorbide_mononitrate
Organisms Affected: Humans and other mammals