Home Drug Guide Isosorbide Mononitrate

Drug Guide

Generic Name

Isosorbide Mononitrate

Brand Names Ismo, Monoket, Imdur

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/A

Drug-Herb Interactions

N/A

Nursing 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.

🛡️ 5 Critical Medication Safety Tips for Nurses

1

Triple-Check High-Risk Medications

Always have another nurse verify insulin, heparin, warfarin, and chemotherapy drugs. These "high-alert" medications cause the most serious errors. Check concentration, dose calculation, and pump settings twice.

2

Know Look-Alike, Sound-Alike Drugs

Common mix-ups: hydromorphone/morphine, Celebrex/Celexa, Zyprexa/Zyrtec. Always use BOTH generic and brand names, read labels twice, and use barcode scanning when available. One wrong letter can be fatal.

3

Assess Before AND After Giving Meds

Check vitals before cardiac meds, pain levels before analgesics, and blood glucose before insulin. Always reassess within 30 minutes to evaluate effectiveness and watch for adverse reactions.

4

Watch for Drug Interactions

Common dangerous combinations: warfarin + aspirin (bleeding), ACE inhibitors + potassium (hyperkalemia), digoxin + diuretics (toxicity). Always check drug interactions before administering new medications.

5

Educate Your Patients

Teach patients medication names, purposes, major side effects, and what to report. Informed patients catch errors and improve compliance. Always encourage questions - an educated patient is a safer patient.

⚡ Remember: When in doubt, don't give it out! It's always safer to double-check than regret later.

⚠️ Medical Disclaimer

This drug guide is for educational purposes only and is NOT intended for clinical use. Always consult current prescribing information, healthcare providers, and institutional protocols before administering any medication. Do not use this information for patient care decisions.