Isosorbide dinitrate

Pronunciation: eye-so-SOR-bide dye-NYE-trate.

Generic name
isosorbide dinitrate
Drug class
Organic nitrate vasodilator
Form
Tablet (5-40 mg strengths depending on country); sublingual tablet in some markets
Route
Oral (also available as an injectable/infusion in some countries)
Legal status
Prescription-only

Availability and supply rules vary by country

Trade names by country: United States · United Kingdom · Canada · Australia

Australia: Isordil / Sorbidin (6) · Full directory

What isosorbide dinitrate is and how it works

Isosorbide dinitrate is a prescription-only nitrate medicine that widens (dilates) blood vessels, reducing the heart's workload and improving blood flow to the heart muscle. It is used to prevent angina (chest pain from reduced blood flow to the heart), not to treat a sudden attack already in progress. (1) (2)

Take isosorbide dinitrate exactly as your prescriber directs, following the specific timing schedule you are given -- this timing is deliberately designed to include a nitrate-free period each day to keep the medicine working well. It is critically important to tell your prescriber about any use of erectile dysfunction medicines (sildenafil, tadalafil, vardenafil) or pulmonary hypertension medicines (such as riociguat), since combining these with isosorbide dinitrate can cause a severe, life-threatening drop in blood pressure.

Mechanism of action: how isosorbide dinitrate works

Isosorbide dinitrate is metabolised to isosorbide mononitrate (an active metabolite) and releases nitric oxide in vascular smooth muscle, activating guanylate cyclase and increasing cGMP, producing venous and arterial vasodilation that reduces cardiac preload and afterload and improves coronary blood flow distribution. (1) (2) (3)

What isosorbide dinitrate is used for

Prevention of angina pectoris

Used regularly to prevent episodes of angina (chest pain) caused by coronary artery disease. It works too slowly to relieve a sudden angina attack already happening -- a fast-acting nitrate (such as sublingual glyceryl trinitrate) is used for that instead, as directed by a prescriber. (1) (2)

Heart failure (adjunct treatment, UK/EU)

In the UK and some EU countries, also used as an add-on treatment for congestive heart failure alongside other standard heart failure medicines, as directed by a prescriber. (2) (3)

Before taking isosorbide dinitrate

Do not take / not appropriate for

  • Do not take isosorbide dinitrate together with sildenafil, tadalafil, vardenafil, or any other PDE5-inhibitor medicine (often used for erectile dysfunction or pulmonary hypertension) -- combining these can cause a sudden, severe, and potentially fatal drop in blood pressure. (all countries) (1) (2) (3)
  • Do not take isosorbide dinitrate together with riociguat (a medicine for pulmonary hypertension) -- the combination is contraindicated for the same reason, severe hypotension. (all countries) (1) (3)
  • Do not take isosorbide dinitrate if you have severe low blood pressure, are in shock, have had a recent heart attack with low filling pressures, or have raised pressure inside the skull. (all countries) (2) (3)

Tell your clinician about

  • Any use of erectile dysfunction medicines or pulmonary hypertension medicines -- this is essential for your safety.
  • Any history of low blood pressure, fainting, severe anaemia, or recent heart attack.
  • All other medicines you take, especially other blood-pressure-lowering or vasodilator medicines, and alcohol use.
  • Pregnancy, plans for pregnancy, or breastfeeding.
  • Any lactose or sucrose intolerance, since some formulations contain these.
(1) (2) (3)

How to take isosorbide dinitrate

  • Take isosorbide dinitrate exactly as prescribed, at the specific times of day set for you -- the schedule is designed to include a nitrate-free interval (commonly at least 14 hours) each day, since continuous round-the-clock use reduces how well the medicine works over time.
  • Swallow tablets as directed; some formulations (sublingual) are designed to dissolve under the tongue instead -- follow your product's specific instructions.
  • Do not change your dosing schedule on your own, even if you get headaches -- headache is a common, expected effect and a marker that the medicine is active; discuss any headache with your prescriber or pharmacist, who can suggest ways to manage it (such as paracetamol/acetaminophen) without reducing the medicine's effectiveness.
(1) (2)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4) (5) (6)

Missed dose

If you miss a dose, take it when you remember unless it is close to your next scheduled dose -- in that case, skip the missed dose and continue your regular schedule. Do not take a double dose. Contact your prescriber or pharmacist if you are unsure, since the timing of doses (including the nitrate-free interval) matters for this medicine.

Overdose

Seek urgent medical attention if you think you have taken too much isosorbide dinitrate or have symptoms such as severe dizziness, fainting, a very fast or pounding heartbeat, or a severe headache with visual disturbance -- overdose can cause dangerously low blood pressure. (1) (2)

Side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms.

Headache -- often frequent, especially when starting treatment; this is a marker that the medicine is working and usually eases over time.

What to notice: Headache -- often frequent, especially when starting treatment; this is a marker that the medicine is working and usually eases over time.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1) (2)

Dizziness, lightheadedness, or flushing, especially when standing up quickly.

What to notice: Dizziness, lightheadedness, or flushing, especially when standing up quickly.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (2) (3)

Palpitations (an awareness of your heartbeat) and fatigue.

What to notice: Palpitations (an awareness of your heartbeat) and fatigue.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (2)

Serious warnings

Severe drop in blood pressure (especially if combined with PDE5 inhibitors or riociguat) — boxed_warning

Symptoms: Severe dizziness, fainting, blurred vision, or collapse.

Action: This combination is contraindicated. Seek emergency medical help immediately if you have taken isosorbide dinitrate together with an erectile dysfunction or pulmonary hypertension medicine and feel faint, dizzy, or collapse. (1) (2) (3)

Fainting or severe low blood pressure on standing — emergency

Symptoms: Sudden dizziness, blurred vision, or loss of consciousness, especially after standing up quickly.

Action: Sit or lie down immediately if you feel faint; seek emergency medical help for loss of consciousness or a fall. (2)

Worsening or new chest pain despite treatment (crescendo angina) — emergency

Symptoms: Chest pain that is new, worsening, or not relieved as expected.

Action: Seek emergency medical help immediately, as this can signal a heart attack or that your treatment needs urgent clinician review. (1)

Interactions

  • Sildenafil, tadalafil, vardenafil, and other PDE5-inhibitor medicines -- absolutely contraindicated together due to the risk of severe, potentially fatal low blood pressure. (1) (2) (3)
  • Riociguat -- absolutely contraindicated together for the same reason. (1) (3)
  • Alcohol and other blood-pressure-lowering or vasodilator medicines can add to isosorbide dinitrate's blood-pressure-lowering effect and increase dizziness or fainting risk. (1) (3)
  • Tricyclic antidepressants and other medicines that can lower blood pressure may increase the risk of hypotension when combined with isosorbide dinitrate. (3)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

Safety in pregnancy has not been well established. Historic US labeling classified isosorbide dinitrate as pregnancy category C, with animal studies showing effects on the developing fetus only at high doses. Use only if your prescriber decides the benefit outweighs the possible risk. (1) (2) (3) (4) (5) (6)

Breastfeeding

Nitrate medicines pass into breast milk and may affect an infant. Discuss the benefits and risks with your prescriber before breastfeeding while taking isosorbide dinitrate. (1) (2) (3) (4) (5) (6)

Children

Safety and effectiveness in children have not been established in the sources reviewed. (1) (2) (3) (4) (5) (6)

Elderly

Used in elderly patients at similar doses to other adults, with individualised titration; older adults may be more sensitive to blood-pressure-lowering effects. (1) (2) (3) (4) (5) (6)

Hepatic_impairment

Not specifically addressed in the sources reviewed -- tell your prescriber about any liver problems. (1) (2) (3) (4) (5) (6)

Renal_impairment

Not specifically addressed in the sources reviewed -- tell your prescriber about any kidney problems. (1) (2) (3) (4) (5) (6)

Monitoring

Before starting

  • Blood pressure and heart rate
  • Confirmation of angina diagnosis and review of other heart medicines
  • Screening for any current PDE5-inhibitor or riociguat use

During treatment

  • Blood pressure monitoring, especially after dose changes.
  • Watching for headache severity, dizziness, or fainting and discussing these with a prescriber rather than self-adjusting the dose.
  • Review of ongoing need for a nitrate-free interval and overall angina control.
(1) (2)

Storage

Store at room temperature (around 15-25°C/59-77°F), protected from light and moisture. Do not use tablets from a damaged blister. Follow the specific shelf-life and storage instructions on your product's packaging, as these can vary by country and formulation.

Study the drug class: Nitrates

Professional information

Clinician-facing context only, sourced from the current US FDA, UK SmPC, and German Fachinformation reviewed; verify against the current full label before prescribing.

United States

Indication: Prevention of angina pectoris

Dose summary: Individualised; typically 5-20 mg two or three times daily initially, maintenance 10-40 mg two or three times daily, with an eccentric schedule preserving a nitrate-free interval of at least ~14 hours.

Renal context: Not established in the source reviewed. (1)

United Kingdom

Indication: Angina prophylaxis and adjunct heart failure treatment

Dose summary: Individualised; typically one or two tablets three or four times daily for adults and elderly patients.

Renal context: Not established in the source reviewed. (2)

Mechanism of action

Hepatic guidance

Not specifically addressed in the sources reviewed for this dossier.

Overdose note

Overdose produces exaggerated vasodilation: hypotension, reflex tachycardia, headache, and potentially methaemoglobinaemia at very high doses; manage supportively with supine positioning, volume support, and monitoring; PDE5-inhibitor or riociguat co-ingestion markedly increases severity. (1) (2) (3)

Frequently asked questions

Is isosorbide dinitrate available in the US, UK, Europe, Canada, Australia, and New Zealand?

It is confirmed available in the US, UK, the EU (Germany and other member states -- note a French presentation, Risordan, was discontinued in 2022), Canada, and Australia. For New Zealand, this review could not locate a dedicated, currently marketed data sheet for isosorbide dinitrate itself, so its current New Zealand status is honestly marked as unable to verify rather than assumed. (1) (2) (3) (4) (5) (6)

Can I take isosorbide dinitrate with sildenafil (Viagra) or similar medicines?

No. This combination is contraindicated and can cause a severe, life-threatening drop in blood pressure. Always tell every prescriber about all your medicines, including any erectile dysfunction or pulmonary hypertension treatments. (1) (2) (3)

Why do I get headaches with this medicine, and should I skip a dose to avoid them?

Headache is a common, expected effect of nitrate medicines and is actually a sign the medicine is working. Do not skip or change your dose on your own to avoid headaches -- discuss headache management, such as using paracetamol/acetaminophen, with your prescriber or pharmacist. (1)

What is the mechanism of action of isosorbide dinitrate?

Isosorbide dinitrate is metabolised to isosorbide mononitrate (an active metabolite) and releases nitric oxide in vascular smooth muscle, activating guanylate cyclase and increasing cGMP, producing venous and arterial vasodilation that reduces cardiac preload and afterload and improves coronary blood flow distribution. (1) (2) (3)

What is the generic name of Isosorbide dinitrate?

The generic name is isosorbide dinitrate. (1) (2)

What class of drug is isosorbide dinitrate?

Isosorbide dinitrate is classed as: Organic nitrate vasodilator. (1) (2)

References

  1. Isosorbide Dinitrate Tablets -- full prescribing informationU.S. Food and Drug Administration / DailyMed (NIH), full prescribing information · United States · dated 2026-01-01 · accessed 2026-07-29 · source 1
  2. Isosorbide Dinitrate Tablets 20 mg -- Summary of Product Characteristicselectronic medicines compendium (emc), United Kingdom -- Chemidex Pharma Ltd · United Kingdom · dated 2026-01-01 · accessed 2026-07-29 · source 2
  3. ISDN-ratiopharm (Isosorbiddinitrat) FachinformationGerman Fachinformation directory (fachinfo.de) -- ISDN-ratiopharm, an isosorbide dinitrate product currently marketed in Germany (EU member state) · European Union · dated 2020-11-01 · accessed 2026-07-29 · source 3
  4. RISORDAN 20 mg, comprime secable -- marketing authorisation statusBase de données publique des médicaments (French official public medicines database, ANSM-linked) · European Union (France) · dated 2022-02-14 · accessed 2026-07-29 · source 4
  5. ISDN (Isosorbide Dinitrate Tablets) Product Monograph; Isordil Titradose (DIN 00208973)Health Canada product monograph / Drug Product Database · Canada · dated 2026-01-01 · accessed 2026-07-29 · source 5
  6. ISORDIL / SORBIDIN isosorbide dinitrate -- ARTG registrationsTherapeutic Goods Administration (TGA), Australia · Australia · dated 2026-01-01 · accessed 2026-07-29 · source 6

Brand names by country

Single-ingredient isosorbide dinitrate names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

  • Isosorbide dinitrate (generic; formerly Isordil) (1)FDA approved currently labeled · 5 mg, 10 mg, 20 mg, 30 mg, 40 mg · multiple generic manufacturers

United Kingdom

  • Isosorbide Dinitrate Tablets (2)MHRA licensed emc smpc confirmed · 10 mg, 20 mg · Chemidex Pharma Ltd

Canada

  • ISDN

Australia

  • Isordil / Sorbidin (6)TGA ARTG registered confirmed · 5 mg, 10 mg, 30 mg, 40 mg · Arrotex Pharmaceuticals Pty Ltd
View brands in additional countries.

European Union

ISDN-ratiopharm / Nitrosorbon / Maycor / IsoMack / Isoket (Germany) (3), Risordan (France) -- discontinued (4)

This page provides general reference information about isosorbide dinitrate and is not a substitute for advice from the prescriber managing your treatment. All dosing and treatment decisions should be made with your prescriber.

Related medicines