188 Section 4/ Drugs Acting on Cardiovascular & Urinary Systemact by inhibiting the uptake and degrada-
tion of adenosine (a local mediator involved
in auto regulation of coronary flow in re-
sponse to ischemia). It has also weak plate-
let inhibiting action. It reversibly inhibits
platelet phosphodiesterase hence cAMP
concentration is increased and there is re-
duction of platelet reactivity.
Adverse effects include nausea, dizzi-
ness, skin rash and headache. Though it is
not useful as an antianginal drug, but it has
been employed for prophylaxis of coronary
and cerebral thrombosis in post MI and
post stroke patients, as well as to prevent
thrombosis in patients with prosthetic heart
valves.