'Coronary steal' phenomenon is uased by?
Ans. A. Dipyridamole. (Ref. KDT 6th/Pg. 609; Harrisonys Internal Medicine 17th /PG 738).# Dipyridamol or persantin causes coronary steal phenomenon. It dilates resistant coronary vessels and diverts blood from ischaemic zone to non-ischaemic zone leading to "coronary steal phenomenon."# It is used for assessment of myocardial injury by dipyridamol-induced stress scan.DIPYRIDAMOL (PERSANTIN)IntroductionDipyridamole is a relatively weak antiplatelet agent on its own, but an extended-release formulation of dipyridamole combined with low-dose aspirin, a preparation known as Aggrenox, is used for prevention of stroke in patients with transient ischemic attacks.Mechanism of ActionBy inhibiting phosphodiesterase, dipyridamole blocks the breakdown of cAMP.Increased levels of cAMP reduce intracellular calcium and inhibit platelet activation.Dipyridamole also blocks the uptake of adenosine by platelets and other cells.This produces a further increase in local cAMP levels because the platelet adenosine A2 receptor is coupled to adenylate cyclase.Side EffectsBecause dipyridamole has vasodilatory effects, it must be used with caution in patients with coronary artery disease (coronary steal phenomenon).Coronary steal phenomenon can also be caused by adenosine.GI complaints, headache, facial flushing, dizziness, and hypotension can also occur. These symptoms often subside with continued use of the drug.IndicationsDipyridamole plus aspirin was compared with aspirin or dipyridamole alone, or with placebo, in patients with an ischemic stroke or transient ischemic attack.Aggrenox is often used for stroke prevention.However, because of its vasodilatory effects and the paucity of data supporting the use of dipyridamole in patients with symptomatic coronary artery disease,Aggrenox should not be used for stroke prevention in such patients.
Dipyridamole
Verapamil
Diltiazim
Nicorandil
C.V.S