Cyclic Nucleotide Phosphodiesterase Inhibitors

Dipyridamole is a cyclic nucleotide phosphodiesterase inhibitor that increases levels of cAMP, which decreases thromboxane A2 levels.  Thromboxane A2 promotes platelet adhesion.  Dipyridamole also causes vasodilation via increased cAMP levels.  Dipyridamole is used for stroke prophylaxis. Bleeding and coronary steal phenomenon can occur after initiating dipyridamole.  

Class Drugs

• Dipyridamole

Class Mechanism of Action

Inhibits cyclic nucleotide phosphodiesterase

• Increases intracellular cAMP, which decreases thromboxane A2

• Decreased thromboxane ultimately lowers platelet adhesion

Increased cAMP levels result in vasodilation

Class Applications

Prophylaxis of stroke

Class Adverse Effects

Bleeding

Coronary steal phenomenon: vasodilation reduces blood flow to coronary arteries thereby worsening myocardial oxygen supply

Drug Table

Drug Name	Application	Comments	Image
Dipyridamole	Prophylaxis of stroke (often combined with aspirin)	Mechanism of Action; Inhibits cyclic nucleotide phosphodiesterase, increasing cAMP, which decreases thromboxane A2 and lowers platelet adhesion; Increased cAMP also causes vasodilation; Adverse Effects; Bleeding; Coronary steal phenomenon (vasodilation reduces blood flow to coronary arteries, worsening myocardial oxygen supply)	"Dice" "Pyramid" "Mole"