Isosorbide Mononitrate (Imdur, ISMO, Monoket)


  • Cardiac


  • Antianginal agent


  • Prevention of angina pectoris

  • Hypertension (acute) (non-FDA approved)


  • Hypersensitivity to nitrates, severe anemia, close-angle glaucoma, postural hypotension

  • Head trauma


  • Pregnancy category C; use caution in nursing mothers

  • Acute MI, hypertrophic cardiomyopathy, glaucoma

  • Volume depletion, hypotension, abrupt withdrawal

  • Continuous delivery without nitrate-free interval (tolerance develops)

Adverse Reactions (Side Effects):

  • CNS: agitation, anxiety, apprehension, confusion, dizziness, dyscoordination, headache, hypoesthesia, hypokinesia, insomnia, nervousness, nightmares, restlessness, vertigo, weakness

  • CV: atrial fibrillation, cardiovascular collapse, crescendo angina, dysrhythmias, edema, hypotension, PVCs, rebound hypertension, retrosternal discomfort, syncope, tachycardia

  • EENT: blurred vision, diplopia

  • GI: abdominal pain, diarrhea, dyspepsia, involuntary passing of feces, nausea, tenesmus, vomiting

  • GU: dysuria, impotence, involuntary passing of urine, urinary frequency

  • HEME: hemolytic anemia, methemoglobinemia

  • MS: arthralgia, muscle twitching

  • SKIN: cold sweat, crusty skin lesions, exfoliative dermatitis, flushing, pallor, perspiration, pruritis, rash



Administered orally: Asymmetric dosing regimens provide a daily nitrate-free interval to minimize the development of tolerance.

  • Adult:   

    • PO 5-20mg 2 times daily (with the 2 doses 7 hours apart); 

    • PO SUS REL 30-60mg 1 time daily initially, titrate to 120-240mg 1 time daily if necessary

Special considerations:

  • Headache may be a marker for drug activity; do not try to avoid by altering treatment schedule; aspirin or acetaminophen may be used for relief

  • Dissolve SL tablets under tongue; do not crush, chew, or swallow

  • Do not crush chewable tablets before administering

  • Avoid alcohol

  • Make changes in position slowly to prevent fainting


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