Classes
DEA Class; Rx
Common Brand Names; Imdur, Monoket, ISMO
- Nitrates, Angina
Description
Organic nitrate that causes systemic venodilation, decreasing preload; enters vascular smooth muscle and is converted to nitric oxide, leading to activation of cyclic guanosine monophosphate and vasodilation
Relaxes smooth muscle via dose-dependent dilation of arterial and venous beds to reduce both preload and afterload, as well as myocardial oxygen demand; also improves coronary collateral circulation, lowering blood pressure, increasing heart rate, and causing occasional paradoxical bradycardia
Indications
Contraindications
Hypersensitivity to organic nitrates
PDE-5 inhibitors (eg, avanafil, sildenafil, tadalafil, or vardenafil); concomitant use can cause severe hypotension, syncope, or myocardial ischemia
Concomitant administration with guanylate stimulator riociguat (may cause hypotension)
Adverse Effects
- Dizziness
- Flushing
- Headache
- Hypotension
- Methemoglobinemia
- Nausea
- Orthostatic hypotension
- Palpitations
- Restlessness
- Syncope
- Tachycardia
- Vomiting
Warnings
Use caution in acute myocardial infarction, alcohol use, hyperthyroidism, increased intracranial pressure (eg, from head trauma or cerebral hemorrhage; potential contraindication), increased intraocular pressure, postural hypotension, volume depletion, Moderate hypotension, low systolic blood pressure (BP)
Not recommended for use in patients with acute myocardial infarction or heart failure
May cause CNS depression, which may in turn impair physical or mental abilities; caution patient about performing tasks that require mental alertness, including operating heavy machinery
Avoid use in patients with hypertrophic cardiomyopathy with outflow tract obstruction; nitrates may reduce preload, which can exacerbate obstruction and cause hypotension or syncope and/or worsening of heart failure
Do not change brands unintentionally; formulations are not all bioequivalent; extended release formulation not intended for the immediate relief of acute attacks of angina pectoris
Treat drug-induced headache with aspirin or acetaminophen
Provide nitrate-free interval (10-12 hr or overnight) to prevent development of tolerance
Severe hypotension may occur along with paradoxical bradycardia and increased angina pectoris; ethanol can cause severe hypotension with even small doses; avoid excessive, prolonged hypotension
Withdraw gradually to prevent acute angina
Discontinue if blurred vision develops
Use supportive treatment to manage overdose
Narrow-angle glaucoma (controversial: may not be clinically significant)
Pregnancy and Lactation
Pregnancy category: C
Lactation: Unknown whether drug crosses into breast milk; use caution
Maximum Dosage
Immediate release: 5-10 mg PO twice daily initially (5 mg in small patients) given each dose 7 hr apart; increased to 10 mg PO q12hr by day 2 or 3; maintenance: 20 mg PO q12hr
Extended release: 30-60 mg PO once daily in the morning initially; may be increased to 120 mg PO once daily; wait at least 3 days between increases; if warranted may increase up to 240 mg PO once daily (rare)
Pediatric
Safety and efficacy not established
How supplied
Isosorbide mononitrate
tablet
- 10mg
- 20mg
tablet, extended release
- 30mg
- 60mg
- 120mg
