ISOSORBIDE MONONITRATE
(eye-soe-sor'bide)
Ismo, Imdur, Monoket
Classifications: cardiovascular agent; nitrate vasodilator
Prototype: Nitroglycerin
Pregnancy Category: C (category B for sustained release form)
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10 mg, 20 mg tablets; 30 mg, 60 mg, 120 mg sustained release tablets
Isosorbide mononitrate is a long-acting metabolite of the coronary vasodilator isosorbide dinitrate. It decreases preload
as measured by pulmonary capillary wedge pressure (PCWP), and left ventricular end volume and diastolic pressure (LVEDV),
with a consequent reduction in myocardial oxygen consumption.
It is equally or more effective than isosorbide dinitrate in the treatment of chronic, stable angina. It is a potent vasodilator
with antianginal and antiischemic effects.
Prevention of angina. Not indicated for acute attacks.
Hypersensitivity to nitrates; severe anemia; closed-angle glaucoma, postural hypotension, head trauma, cerebral hemorrhage
(increases intracranial pressure). Safe use during pregnancy [(category C) and (category B) for sustained form] or lactation
is not established.
Older adults, hypotension.
Prevention of Angina
Adult: PO Regular release (ISMO, Monoket) 20 mg b.i.d. 7 h apart; Sustained release (Imdur) 30–60 mg every morning, may increase
up to 120 mg once daily after several days if needed (max: dose 240 mg)
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Oral
- Give first dose in morning on arising and second dose 7 h later with twice daily dosing regimen. Give in morning on arising
with once daily dosing.
- Store sustained release tablets in a tight container.
CNS: Headache, agitation, anxiety, confusion, loss of coordination, hypoesthesia, hypokinesia, insomnia or somnolence, nervousness,
migraine headache, paresthesia, vertigo, ptosis, tremor. CV: Aggravation of angina, abnormal heart sounds, murmurs, MI, transient hypotension, palpitations. Hematologic: Hypochromic anemia, purpura, thrombocytopenia, methemoglobinemia (high doses). GI: Nausea, vomiting, dry mouth, abdominal pain, constipation, diarrhea, dyspepsia, flatulence, tenesmus, gastric ulcer, hemorrhoids,
gastritis, glossitis. Metabolic: Hyperuricemia, hypokalemia. GU: Renal calculus, UTI, atrophic vaginitis, dysuria, polyuria, urinary frequency, decreased libido, impotence. Respiratory: Bronchitis, pneumonia, upper respiratory tract infection, nasal congestion, bronchospasm, coughing, dyspnea, rales, rhinitis. Skin: Rash, pruritus, hot flashes, acne, abnormal texture. Special Senses: Diplopia, blurred vision, photophobia, conjunctivitis.
Drug: Alcohol may cause severe hypotension and cardiovascular collapse. Aspirin may increase nitrate serum levels. calcium channel blockers may cause orthostatic hypotension.
Absorption: Completely and rapidly absorbed from GI tract; 93% reaches systemic circulation. Onset: 1 h. Peak: Regular release 30–60 min; sustained release 3–4 h. Duration: Regular release 5–12 h; sustained release 12 h. Metabolism: Metabolized in liver by denitration and conjugation to inactive metabolites. Elimination: Excreted primarily by kidneys. Half-Life: 4–5 h.
Assessment & Drug Effects
- Monitor cardiac status, frequency and severity of angina, and BP.
- Assess for and report possible S&S of toxicity, including orthostatic hypotension, syncope, dizziness, palpitations, light-headedness,
severe headache, blurred vision, and difficulty breathing.
- Lab tests: Monitor serum electrolytes periodically.
Patient & Family Education
- Do not crush or chew sustained release tablets. May break tablets in two and take with adequate fluid (4–8 oz).
- Do not withdraw drug abruptly; doing so may precipitate acute angina.
- Maintain correct dosing interval with twice daily dosing.
- Note: Geriatric patients are more susceptible to the possibility of developing postural hypotension.
- Avoid alcohol ingestion and aspirin unless specifically permitted by physician.
- Do not breast feed while taking this drug without consulting physician.
1%)
Canadian drug name; 
Prototype drug