Dipyridamole

Question 1

Mechanism of action?

Answer 1

Controversial, but the end result is anti-platelet &vasodilatory effects. It increases levels of AMPc that inhibits platelet aggregation which reduces the risk of arterial occlusion. It also blocks cellular uptake of Adenosine prolonging its effect on blood vessels.

Question 2

Indications?

Answer 2

• secondary prevention in cerebrovascular disease.
• first-line option following transient ischemic attack.
• second-line option following ischemic stroke (after Clopidogrel).

Question 3

Important AE?

Answer 3

related to vasodilation : dizziness, rash, headache, flush &gastrointenstinal symptoms, all resolve/improve within time.
risk of bleeding always present, rarely thrombocytopenia.

Question 4

Important interactions?

Answer 4

Doses of Adenosine should be halved when association to Dipyridamole.
Interactions with other anti-platelet/anticoagulant drugs.

Question 5

How is Dipyridamole taken ?

Answer 5

Orally, modified-release preparations are strongest, twice daily &taken for life, better with food. Protocol is to increase doses progressively to prevent side effects until reaching 200mg twice daily. Modified release preparations are to be taken whole, without chewing or crushing.