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Isosorbide mononitrate oral

Updated 2 Feb 2023 | Longer acting nitrates


Standard release formulations of isosorbide mononitrate.

Drugs List

  • CARMIL 20mg tablets
  • CARMIL 40mg tablets
  • ISMO 10 tablets
  • ISMO 20 tablets
  • isosorbide mononitrate 10mg tablets
  • isosorbide mononitrate 20mg tablets
  • isosorbide mononitrate 30mg tablets
  • isosorbide mononitrate 40mg tablets
  • Therapeutic Indications


    Congestive heart failure (resistant to other treatment)
    Prophylaxis of angina pectoris
    Treatment of angina pectoris



    Those who have not previously received nitrates
    The recommended initial dose is 10 to 40 mg twice daily.

    Those who have previously received nitrates
    Initially 10 to 40 mg 2 to 3 times daily. Up to 120 mg daily in divided doses if required.

    Most patients will require 40 to 60 mg daily in divided doses.

    Patients taking one tablet twice daily, the second dose should be taken 8 hours after the first dose. If the dose is one tablet three times a day, take one every 6 hours and ensure 12 hours treatment free interval every 24 hours.


    (See Dosage; Adult)

    Additional Dosage Information

    Patients being transferred from sustained release formulations should be initiated at half their previous dosage.


    Children under 18 years
    Low cardiac filling pressures
    Systolic blood pressure < 90mmHg
    Aortic stenosis
    Cardiac tamponade
    Cerebrovascular haemorrhage
    Circulatory failure
    Constrictive pericarditis
    Head trauma
    Hypertrophic obstructive cardiomyopathy
    Low filling pressure - if treating acute myocardial infarction
    Mitral stenosis
    Narrow angle glaucoma
    Raised intracranial pressure
    Severe anaemia
    Toxic pulmonary oedema

    Precautions and Warnings

    Predisposition to narrow angle glaucoma
    Ventilation-perfusion mismatch
    Glucose-galactose malabsorption syndrome
    Lactose intolerance
    Left ventricular failure
    Recent myocardial infarction
    Severe hepatic impairment
    Severe renal impairment

    Advise ability to drive/operate machinery may be affected by side effects
    Not all available brands are licensed for all indications
    Some formulations contain lactose
    Assess patient's tolerance to treatment
    Tolerance may occur with prolonged use of large doses
    Avoid abrupt withdrawal
    Maintain treatment at the lowest effective dose
    Advise patient to moderate alcohol intake during treatment
    Hypotensive effect enhanced by alcohol
    Advise patient not to use for relief of acute attacks
    Advise patient on possible rebound phenomena on withdrawal

    After the first dose, symptoms of circulatory collapse may occur, particularly in patients with labile circulation.

    Nitrates may induce hypotension which may be accompanied by paradoxical bradycardia and increased angina.

    Pregnancy and Lactation


    Use isosorbide mononitrate with caution during pregnancy.

    The manufacturer does not recommend using isosorbide mononitrate during pregnancy and notes that its use should only be considered if the possible benefits of treatment outweigh the risks. Some animal studies have shown teratogenic effects in doses up to 500mg/kg/day such as significant increases in prolonged gestation, prolonged parturition, still birth and neonatal death (Briggs, 2015). Human data is limited and as such a potential risk cannot be ruled out.


    Use isosorbide mononitrate with caution during breastfeeding.

    The manufacturer advises caution if isosorbide mononitrate is used when breastfeeding. The presence of isosorbide mononitrate in human breast milk is unknown. Effects on exposed infants are unknown however, due to the short half-life of nitrates, toxic risk to the breastfed infant is not expected (Schaefer, 2015).

    Side Effects

    Allergic skin reactions
    Circulatory collapse
    Exfoliative dermatitis
    Orthostatic hypotension
    Reflex tachycardia
    Transient hypoxaemia
    Worsening of angina


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Further Information

    Last Full Review Date: September 2013

    Reference Sources

    Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 3rd edition (2015) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

    Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 10th edition (2015) ed. Briggs, G., Freeman, R. Wolters Kluwer Health, Philadelphia.

    Martindale: The Complete Drug Reference, 37th edition (2011) ed. Sweetman, S. Pharmaceutical Press, London.

    Summary of Product Characteristics: Ismo 10. Durbin Plc. Revised October 2007.
    Summary of Product Characteristics: Ismo 20. Durbin Plc. Revised October 2007.
    Summary of Product Characteristics: Ismo 40. Durbin Plc. Revised October 2007.

    Summary of Product Characteristics: Isosorbide mononitrate 30mg tablets. Medreich PLC. Revised June 2021.

    Summary of Product Characteristics: Isosorbide Mononitrate/Carmil/Monomil 20mg Tablets. Aurobindo Pharma - Milpharm Ltd. Revised March 2019.
    Summary of Product Characteristics: Isosorbide Mononitrate/Carmil/Monomil 40mg Tablets. Aurobindo Pharma - Milpharm Ltd. Revised March 2019.

    Summary of Product Characteristics: Elantan 10. UCB Pharma Ltd. Revised September 2008.
    Summary of Product Characteristics: Elantan 20. UCB Pharma Ltd. Revised February 2008.
    Summary of Product Characteristics: Elantan 40. UCB Pharma Ltd. Revised March 2009.

    NICE Evidence Services Available at: Last accessed: 09 November 2022

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