Evigrade

Isosorbide mononitrate

AEMPS

Long-acting organic nitrate

ATC code: C01DA14

Updated · Methodology

Indications

A

Stable angina

First line

First-line for long-term prevention of stable angina attacks per 2024 alongside β-blockers and calcium channel blockers. Dose 40–60 mg once daily in the morning in extended-release form. Reduces preload and improves coronary flow. Does not affect mortality or cardiovascular outcomes – a symptomatic agent. For acute attacks, sublingual nitroglycerin is used.

ICD-10: I20.8 · ICD-11: BA40.1

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

F

Athletic endurance

Not recommended

Isosorbide mononitrate is a long-acting organic nitrate. It is prescribed for angina prophylaxis ( 2024). In sports circles, isosorbide mononitrate is occasionally promoted to improve blood flow to muscles. In healthy athletes without ischemic heart disease, no clinical studies of prophylactic use exist. The drug has specific risks: headache (common, marked), hypotension with syncope, tolerance with regular use, and dangerous blood pressure drop combined with PDE5 inhibitors (strictly contraindicated). If isosorbide mononitrate was prescribed to an athlete, consider seeking a second opinion.

How to read tiers A–F
  • AStrong evidence – first or second line in international guidelines
  • BRecommended in selected cases
  • CStudy data contradict each other
  • DBenefit not proven, no documented harm
  • FDocumented harm, or risk without benefit

Mechanism of action

Denitrated in endothelial and vascular smooth muscle cells by mitochondrial aldehyde dehydrogenase to nitric oxide (NO). NO activates soluble guanylate cyclase, raises cGMP, and relaxes vascular smooth muscle. Predominantly dilates veins – lowering cardiac preload; at higher doses also dilates arteries – lowering afterload. No first-pass hepatic metabolism unlike isosorbide dinitrate – bioavailability 100%, half-life 5 hours. Extended-release form dosed once daily.

Safety

Contraindications

  • Nitrate hypersensitivity
  • Hypotension and cardiogenic shock
  • Hypovolemia
  • Hypertrophic obstructive cardiomyopathy
  • Severe aortic stenosis
  • Concomitant PDE-5 inhibitors
  • Concomitant riociguat
  • Angle-closure glaucoma
  • Severe anemia

Serious adverse effects

  • Severe hypotension (especially with PDE-5 inhibitors)
  • Methemoglobinemia (at high doses)
  • Paradoxical bradycardia and syncope
  • Nitrate tolerance with continuous use

Common adverse effects

  • Headache (especially in early days)
  • Dizziness
  • Hypotension and orthostatic reactions
  • Reflex tachycardia
  • Facial flushing

Pregnancy: can you take Isosorbide mononitrate?

Limited pregnancy data. Use in pregnancy only when clearly indicated.

Breastfeeding: can you take Isosorbide mononitrate?

Limited data. Use with caution during lactation.

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Practical notes

Timing and administration

Take in the morning at 7–8 am to mimic the circadian rhythm of angina (most attacks in morning hours). A 10–14-hour nitrate-free interval per day is critical to prevent tolerance. Do not combine with PDE-5 inhibitors (sildenafil, tadalafil, vardenafil) – severe hypotension risk (minimum interval 24 hours for sildenafil and vardenafil, 48 hours for tadalafil). When stopping after prolonged use, taper – abrupt stop may worsen angina.

Drug–drug interactions

4 pairs found. Sorted from critical to minor.

CriticalRiociguatSoluble guanylate cyclase (sGC) stimulator

Mechanism

Riociguat activates sGC independently of NO. Nitrate adds NO – synergistic systemic hypotension. Adempas Section 4.3.

Symptoms

Severe hypotension.

Management

Combination contraindicated.

Pair details →Riociguat →

CriticalSildenafilPhosphodiesterase type 5 inhibitors (PDE5)

Mechanism

Sildenafil inhibits PDE-5; isosorbide mononitrate releases nitric oxide. Both pathways converge on cGMP accumulation in vascular smooth muscle, causing severe systemic vasodilation. Blood pressure drops to shock levels with risk of myocardial infarction and stroke. contraindicates PDE-5 inhibitors with any nitrate.

Symptoms

Sudden hypotension within an hour: dizziness, syncope, tachycardia, pallor, loss of consciousness. Cardiac arrest possible.

Management

Combination contraindicated. Allow at least 24 hours between the last sildenafil dose and any nitrate (48 hours for tadalafil). A patient with angina who has taken sildenafil should not receive nitrates – use morphine, oxygen and urgent angiography.

Pair details →Sildenafil →

CriticalTadalafilPhosphodiesterase type 5 (PDE-5) inhibitor

Mechanism

Both activate cGMP pathway. Synergistic systemic vasodilation – fatal hypotension with MI. Tadalafil's long T1/2 requires 48-hour washout.

Symptoms

Sudden hypotension, MI.

Management

Combination contraindicated. 48 hours between tadalafil and nitrate.

Pair details →Tadalafil →

CriticalVardenafilPhosphodiesterase type 5 (PDE-5) inhibitor

Mechanism

Same pharmacodynamics – synergistic hypotension.

Symptoms

Fatal hypotension.

Management

Combination contraindicated. 24-hour washout.

Pair details →Vardenafil →

Label mentions14 mentions

Verbatim lines from the interaction sections, in the language of the label

From this drug’s label

  • CriticalPDE5 inhibitorsclass named in the label
    «CONTRAINDICATIONS: Do not use isosorbide mononitrate in patients who are taking certain drugs for erectile dysfunction (phosphodiesterase inhibitors), such as sildenafil, tadalafil, or vardenafil…»

    FDA, section 4 · Open on DailyMed

  • CriticalRiociguat
    «CONTRAINDICATIONS: Do not use isosorbide mononitrate in patients who are taking the soluble guanylate cyclase stimulator riociguat. Concomitant use can cause hypotension.»

    FDA, section 4 · Open on DailyMed

  • CriticalSildenafil
    «Los pacientes en tratamiento con este preparado no deben recibir la administración concomitante de inhibidores de la 5-fosfodiesterasa como el sildenafilo para la disfunción eréctil (véase sección…»

    AEMPS, section 4.3 · Open on CIMA

  • CriticalSildenafil
    «CONTRAINDICATIONS: Do not use isosorbide mononitrate in patients who are taking certain drugs for erectile dysfunction (phosphodiesterase inhibitors), such as sildenafil, tadalafil, or vardenafil…»

    FDA, section 4 · Open on DailyMed

  • CriticalTadalafil
    «CONTRAINDICATIONS: Do not use isosorbide mononitrate in patients who are taking certain drugs for erectile dysfunction (phosphodiesterase inhibitors), such as sildenafil, tadalafil, or vardenafil…»

    FDA, section 4 · Open on DailyMed

  • CriticalVardenafil
    «CONTRAINDICATIONS: Do not use isosorbide mononitrate in patients who are taking certain drugs for erectile dysfunction (phosphodiesterase inhibitors), such as sildenafil, tadalafil, or vardenafil…»

    FDA, section 4 · Open on DailyMed

  • Moderatecalcium channel blockersclass named in the label
    «Drug Interactions: Marked symptomatic orthostatic hypotension has been reported when calcium channel blockers and organic nitrates were used in combination. Dose adjustments of either class of agents…»

    FDA, section 7 · Open on DailyMed

  • antagonistas del calcioclass named in the label
    «El efecto vasodilatador del mononitrato de isosorbida puede intensificarse por la administración concomitante de otros fármacos o sustancias que posean un mecanismo de acción antihipertensivo ó…»

    AEMPS, section 4.5 · Open on CIMA

  • antidepresivos tricíclicosclass named in the label
    «El efecto vasodilatador del mononitrato de isosorbida puede intensificarse por la administración concomitante de otros fármacos o sustancias que posean un mecanismo de acción antihipertensivo ó…»

    AEMPS, section 4.5 · Open on CIMA

  • antipsicóticosclass named in the label
    «El efecto vasodilatador del mononitrato de isosorbida puede intensificarse por la administración concomitante de otros fármacos o sustancias que posean un mecanismo de acción antihipertensivo ó…»

    AEMPS, section 4.5 · Open on CIMA

  • betabloqueantesclass named in the label
    «El efecto vasodilatador del mononitrato de isosorbida puede intensificarse por la administración concomitante de otros fármacos o sustancias que posean un mecanismo de acción antihipertensivo ó…»

    AEMPS, section 4.5 · Open on CIMA

  • «El mononitrato de isosorbida puede aumentar el efecto hipertensor de la dihidroergotamina (p.e.incrementando la presión arterial sistólica en bipedestación), debido al aumento de la biodisponibilidad…»

    AEMPS, section 4.5 · Open on CIMA

  • diuréticosclass named in the label
    «El efecto vasodilatador del mononitrato de isosorbida puede intensificarse por la administración concomitante de otros fármacos o sustancias que posean un mecanismo de acción antihipertensivo ó…»

    AEMPS, section 4.5 · Open on CIMA

  • inhibidores de la ECAclass named in the label
    «El efecto vasodilatador del mononitrato de isosorbida puede intensificarse por la administración concomitante de otros fármacos o sustancias que posean un mecanismo de acción antihipertensivo ó…»

    AEMPS, section 4.5 · Open on CIMA

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Frequently asked

What is Isosorbide mononitrate used for?

Isosorbide mononitrate is evaluated for the following indications with varying evidence strength: Stable angina (evidence tier A), Heart failure (evidence tier B), Athletic endurance (evidence tier F). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Isosorbide mononitrate?

Common side effects of Isosorbide mononitrate (≥ 1 in 100): Headache (especially in early days), Dizziness, Hypotension and orthostatic reactions, Reflex tachycardia, Facial flushing. See the Safety section for uncommon and serious reactions.

Is Isosorbide mononitrate safe during pregnancy?

Limited pregnancy data. Use in pregnancy only when clearly indicated.

Is Isosorbide mononitrate compatible with breastfeeding?

Limited data. Use with caution during lactation.

Who should not take Isosorbide mononitrate?

Isosorbide mononitrate is contraindicated in: Nitrate hypersensitivity; Hypotension and cardiogenic shock; Hypovolemia; Hypertrophic obstructive cardiomyopathy; Severe aortic stenosis. Full list in the Safety section.

Official sources

Direct links to regulator labels. Open in a new tab.

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