Isosorbide Mononitrate

Generic Details

Generic Name

Isosorbide Mononitrate

Other Names

  • ISMN
  • Ismo
  • Monoket

Drug Class

  • Vasodilator
  • Nitrate

Chemical Formula

C6H9NO6

Molecular Weight

191.14 g/mol

Mechanism of Action

  • Isosorbide mononitrate is a prodrug that is converted to the active metabolite, nitric oxide (NO), which activates guanylate cyclase leading to increased levels of cyclic guanosine monophosphate (cGMP) causing smooth muscle relaxation and vasodilation.

Indications

  • Angina pectoris
  • Acute heart failure
  • Chronic heart failure

Common Dosage Forms

  • Tablet
  • Extended-release tablet

Typical Dosage

  • 10-60 mg once daily for angina pectoris

Pediatric Dosage

    Geriatric Dosage

    • Initiate at lower doses due to age-related decrease in hepatic function and potential for increased sensitivity

    Side Effects

    • Headache
    • Dizziness
    • Hypotension
    • Flushing
    • Nausea
    • Vomiting

    Contraindications

    • Hypersensitivity to nitrates
    • Severe anemia
    • Severe hypotension
    • Concomitant use with PDE-5 inhibitors (e.g., sildenafil)

    Pregnancy Category

    • C - Risk cannot be ruled out

    Lactation Safety

    • Considered compatible with breastfeeding

    Drug Interactions

    • Concomitant use with other vasodilators or antihypertensive agents may lead to additive hypotensive effects
    • May potentiate the hypotensive effects of alcohol
    • Contraindicated with phosphodiesterase-5 (PDE-5) inhibitors such as sildenafil, tadalafil, vardenafil

    Overdose Symptoms

    • Severe hypotension
    • Headache
    • Tachycardia
    • Methemoglobinemia

    Antidote for Overdose

    • Methylene blue
    • IV fluids
    • Vasopressors if needed for severe hypotension

    Storage Conditions

    • Store at room temperature away from light and moisture

    Pharmacokinetics

    • Absorption: Rapidly absorbed from the GI tract
    • Distribution: Widely distributed, crosses the placenta and enters breast milk
    • Metabolism: Metabolized in the liver to active metabolites
    • Excretion: Mainly excreted in the urine

    Precautions

    • Use with caution in patients with hypothyroidism, hypothermia, closed-angle glaucoma, and in patients with constrictive pericarditis or pericardial tamponade

    Warnings

    • Avoid sudden withdrawal as rebound angina may occur, taper the dose if discontinuing therapy

    Others