Nurses Compass
Drug Guide
Isosorbide Mononitrate
Classification
Therapeutic: Antianginal agent
Pharmacological: Nitrate (vasodilator)
FDA Approved Indications
- Prophylaxis of angina pectoris due to coronary artery disease
Mechanism of Action
Isosorbide mononitrate is a nitrate that converts to nitric oxide in vascular smooth muscle, leading to increased cyclic GMP and resulting in vasodilation. This reduces myocardial oxygen demand by decreasing preload and, to a lesser extent, afterload.
Dosage and Administration
Adult: Typically 30-60 mg once daily in the morning. Dosage may be adjusted based on response and tolerability.
Pediatric: Not approved for pediatric use; safety and efficacy not established.
Geriatric: Start at lower end of dosing range due to increased sensitivity and potential for hypotension.
Renal Impairment: Use with caution; no specific adjustment detailed, assess patient response.
Hepatic Impairment: Use with caution; no specific adjustment detailed, monitor closely.
Pharmacokinetics
Absorption: Well absorbed with high bioavailability due to minimal first-pass metabolism.
Distribution: Widely distributed; volume of distribution approximately 1.3 L/kg.
Metabolism: Metabolized in the liver via conjugation to inactive metabolites.
Excretion: Excreted primarily in urine as inactive conjugates.
Half Life: Approximately 6-8 hours.
Contraindications
- Hypersensitivity to nitrates
- Concurrent use with phosphodiesterase inhibitors (e.g., sildenafil) due to risk of severe hypotension.
Precautions
- Use with caution in patients with hypotension, anemia, increased intracranial pressure, or severe aortic stenosis.
Adverse Reactions - Common
- Headache (Common)
- Dizziness (Common)
- Flushing (Common)
- Weakness (Less common)
Adverse Reactions - Serious
- Severe hypotension (Rare)
- Syncope (Rare)
- Reflex tachycardia (Less common)
Drug-Drug Interactions
- Erectile dysfunction medications (e.g., sildenafil) – risk of severe hypotension
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Monitor blood pressure regularly, assess for signs of hypotension, headache, and tolerance development.
Diagnoses:
- Risk for hypotension
- Risk for impaired tissue perfusion
Implementation: Administer on an empty stomach or as directed, usually once daily in the morning. Educate patient to change positions slowly.
Evaluation: Monitor for relief of angina, monitor blood pressure and heart rate, assess for adverse effects.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Report symptoms of headache, dizziness, or significant hypotension.
- Avoid sudden position changes to prevent orthostatic hypotension.
- Inform about possible development of tolerance.
- Avoid concurrent use of erectile dysfunction drugs.
- Store in a cool, dry place.
Special Considerations
Black Box Warnings:
- None specifically for this medication.
Genetic Factors: No known specific genetic considerations.
Lab Test Interference: None known.
Overdose Management
Signs/Symptoms: Severe hypotension, tachycardia, dizziness, syncope.
Treatment: Position patient supine, monitor vital signs, administer IV fluids if needed, and provide supportive care. Use of vasopressors may be necessary in severe hypotension.
Storage and Handling
Storage: Store at room temperature, away from light and moisture.
Stability: Stable when stored properly; consult manufacturer for specific stability data.