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Organic nitrate

Isosorbide dinitrate

Brand names: Isoket, Cedocard

Isosorbide dinitrate is a nitrate used for the prophylaxis and treatment of angina and as an adjunct in heart failure.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

DOSAGE AND ADMINISTRATION As noted under " CLINICAL PHARMACOLOGY ," multiple-dose studies with isosorbide dinitrate and other nitrates have shown that maintenance of continuous 24-hour plasma levels results in refractory tolerance. Every dosing regimen for isosorbide dinitrate tablets must provide a daily dose-free interval to minimize the development of this tolerance. With immediate-release isosorbide dinitrate, it appears that one daily dose-free interval must be at least 14 hours long. As also noted under " CLINICAL PHARMACOLOGY ," the effects of the second and later doses have been smaller and shorter-lasting than the effects of the first. Large controlled studies with other nitrates …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2026-02-10. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

It is converted to nitric oxide, which relaxes vascular smooth muscle, causing venous and arterial dilatation that reduces cardiac preload, afterload and myocardial oxygen demand.

Prescribing in practice

  • It is contraindicated with phosphodiesterase type-5 inhibitors such as sildenafil because of the risk of severe hypotension.
  • Nitrate tolerance develops with continuous exposure, so dosing should allow a daily nitrate-free interval.
  • Headache and hypotension are common, particularly at the start of treatment.

Monitoring

Monitor blood pressure and angina control, and review for tolerance with regular dosing.

Counselling the patient

  • Do not take medicines for erectile dysfunction such as sildenafil with this medicine.
  • Headache is common early on and usually settles; report fainting or severe dizziness.

Evidence & guidelines

An established nitrate for angina prophylaxis and a recognised adjunct in heart failure in UK practice.

Reference: ESC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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