Dipyridamole

Indications

Dipyridamole is used for: Stroke, Thromboembolism, Transient ischaemic attack

Adult Dose

Oral Thromboembolism Prophylaxis Post-Cardiac Valve Replacement Adult: 75-100 mg PO q6hr as adjunct to warfarin

Child Dose

Oral Thromboembolism Prophylaxis Post-Cardiac Valve Replacement Child: 3-6 mg/kg/day PO divided q6-8hr

Renal Dose

Administration

Should be taken on an empty stomach. Take on an empty stomach 1 hr before meals. May be taken w/ meals to reduce GI discomfort.

Contra Indications

Hypersensitivity. Peptic ulcer.

Precautions

In patients with rapidly worsening angina, subvalvular aortic stenosis, haemodynamic instability associated with recent MI or coagulation disorders esp when given IV during myocardial imaging. Hypotension, unstable angina, aortic stenosis. Pregnancy and lactation. Safety and efficacy are not established in childn < 12 yrs. Lactation: enters breast milk; use with caution

Pregnancy-Lactation

Pregnancy Category: B Lactation: enters breast milk; use with caution

Interactions

Aminophylline may reverse vasodilatation effect. Useful combination with aspirin in prevention of thromboembolism. Efficacy reduced by concurrent admin of antacids. Concurrent use may increase the cardiotoxic effects of adenosine. Potentially Fatal: Potentiates effects of oral anticoagulants and antiarrhythmic agents.

Adverse Effects

Side effects of Dipyridamole : >10% Chest pain (20%), Abnormal ECG (15.9%), Dizziness (12%) 1-10% ST-T changes (7.5%), Abdominal discomfort, oral (6.1%), Extrasystole (5%), Flushing (3.4%), Generalized pain (2.6%), Headache, oral (2.3%) Frequency Not Defined Myocardial infarction (rare), Ventricular arrhythmia (rare), Bronchospasm (rare), Dyspnea

Mechanism of Action

Dipyridamole causes an accumulation of adenosine, adenine nucleotides and cAMP by inhibiting the activity of adenosine deaminase and phosphodiesterase thus inhibiting platelet aggregation and may cause vasodilation.