Antiplatelet — Phosphodiesterase Inhibitor / Adenosine Uptake Inhibitor Pregnancy: There is inadequate evidence of safety in human pregnancy, although the product has been used for many years without apparent ill-consequence; data from use in pregnancy are inadequate and animal studies have shown no hazard of foetal harm. Should only be administered if clearly needed, and not used in pregnancy — especially the first trimester — unless the expected benefit outweighs the possible risk to the foetus. Dipyridamole is excreted in breast milk (about 6% of plasma concentration), so there is a risk of affecting the breast-fed infant — use during breast-feeding only if considered essential by the physician.

Dipyridamole (Secondary Stroke Prevention)

Brand names: Persantin Retard (with aspirin), Asasantin Retard (combined product)

Dipyridamole is an antiplatelet agent used, typically in combination with aspirin, for secondary prevention after ischaemic stroke or transient ischaemic attack (TIA). A modified-release formulation is used for stroke prevention.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: One 200 mg prolonged-release capsule twice daily

Route: Oral — capsules should be swallowed whole without chewing; may be taken with or independently of food

Frequency: Twice daily, usually one in the morning and one in the evening

ALTERNATIVE DOSING FOR INTOLERABLE HEADACHE: in case of intolerable headache at the start of treatment, 1 capsule can be provisionally dosed at bedtime with a low dose of acetylsalicylic acid in the morning; as there are insufficient efficacy data on this alternative dosing and headache usually resolves with regular dosing, the patient should return to normal dosing promptly (within one week). Patients being treated with regular oral doses of dipyridamole should NOT receive additional intravenous dipyridamole; patients on oral dipyridamole who also require pharmacological stress testing with intravenous dipyridamole should discontinue oral dipyridamole for twenty-four hours prior to stress testing. Use with caution in patients with severe coronary artery disease including unstable angina and/or recent myocardial infarction, left ventricular outflow obstruction or haemodynamic instability (e.g. decompensated heart failure), and in patients with coagulation disorders; in myasthenia gravis, adjustment of therapy may be necessary after changes in dipyridamole dosage. Patients with rare hereditary problems of fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency should not take this medicine. ELDERLY: no dosage adjustment is needed. HEPATIC IMPAIRMENT: no dosage adjustment is needed. PAEDIATRIC: not recommended for children, due to lack of data on safety and efficacy. Source: eMC SPC for Dipyridamole 200 mg Prolonged Release Capsules, Hard (§4.2).

Dose adjustments

Renal

No dosage adjustment is needed in patients with renal impairment.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

DOSAGE AND ADMINISTRATION Adjunctive Use in Prophylaxis of Thromboembolism after Cardiac Valve Replacement The recommended dose is 75 to 100 mg four times daily as an adjunct to the usual warfarin therapy. Please note that aspirin is not to be administered concomitantly with coumarin anticoagulants.

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2023-09-16. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Contraindications

Hypersensitivity to the active substance or to any of the excipients

Side effects

Headache and dizziness (very common)
Diarrhoea and nausea (very common); vomiting (common)
Angina pectoris (common); tachycardia, hypotension and hot flush (frequency not known)
Rash and myalgia (common); urticaria, hypersensitivity and angioedema (frequency not known)
Thrombocytopenia and bronchospasm (frequency not known)
Increased bleeding during or after surgery, and post-procedural or operative haemorrhage (frequency not known)

Interactions

Adenosine — dipyridamole increases the plasma levels and cardiovascular effects of adenosine; adjustment of adenosine dosage should be considered if concomitant use is unavoidable
Acetylsalicylic acid — the effects of ASA and dipyridamole on platelet behaviour are additive; addition of dipyridamole to ASA does not increase the incidence of bleeding events
Oral anticoagulants — dipyridamole may enhance their effects; when used with any substances impacting coagulation (anticoagulants and antiplatelets) the safety profile of those medicines must be observed. With warfarin, bleeding was no greater in frequency or severity than with warfarin alone
Blood pressure lowering drugs — dipyridamole may increase the hypotensive effect
Cholinesterase inhibitors — dipyridamole may counteract the anticholinesterase effect, potentially aggravating myasthenia gravis
Alcohol — co-administration may increase the rate of absorption of the prolonged-release capsules

Clinical monograph

How it works

It inhibits platelet aggregation (through effects on adenosine uptake and phosphodiesterase) and acts as a vasodilator. These actions underlie both its antiplatelet effect and its common adverse effects.

Prescribing in practice

Headache is very common when starting, reflecting its vasodilator action — it often limits tolerance but usually settles with continued use; introducing the modified-release form can help.
Vasodilatation can cause flushing, dizziness and hypotension; use with caution in unstable angina, recent myocardial infarction, severe coronary artery disease and aortic stenosis.
It may potentiate other antiplatelet and anticoagulant drugs (increasing bleeding risk); the modified-release preparation should be used for the stroke-prevention indication.

Monitoring

Largely a clinical review: monitor tolerability (especially headache early on), blood pressure and any signs of bleeding when combined with other antithrombotic drugs. Reassess if symptoms are not tolerated or if there are breakthrough vascular events.

Counselling the patient

Headache is common in the first days or weeks and usually eases — continue the medicine and tell us if it is severe or persistent.
Dizziness or flushing can occur; rise slowly from sitting or lying.
Report any unusual bruising or bleeding, particularly if you also take aspirin or other blood-thinning medicines.

Evidence & guidelines

Antiplatelet therapy is guideline-recommended for secondary prevention after ischaemic stroke/TIA (NICE NG128).

Reference: ESPS-2 Trial (Diener et al. JNRS 1996); PRoFESS Trial (NEJM 2008); NICE NG128 (Stroke and TIA); MHRA SPC Persantin Retard; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways