Calcium Channel Blockers Test Questions and Correct Answers

All CCB are racemic mixtures except? Dilt and Nifedipine Non-Dihydropyridines Verapamil and diltiazem Dihydropyridines Nifedipine, Nicardipine, Nimodipine, Felodipine, Isradipine, Nisoldipine Amlodipine, Clevidipine Adverse affects of CCBs are similar except that dihydropyridines never cause what? Bradycardia (usually have reflex tachycardia) CCBs mechanism of action? Bind to unique sites on the a1 subunit of L-type voltage-gated channels Decreasing intracellular calcium Non-dihydropyridines are more selective where? myocardial tissue and the SA/AV node, especially in AV nodal tissue Dihydropyridines are most selective in what type of tissue? arterial vascular smooth muscle cells (do not block SA/AV node) What portion of the L-type channel does verapamil bind to? intracellular portion Blockade by verapamil is enhanced by? frequency of stimulation (works better in increased Heart rates) Phenylalkylamine CCB? verapamil Negative chronotropic effects of verapamil blunt? reflex tachycardia Verapamil is a potent? negative chronotropic and inotropic and dromotropic agent Diltiazem binds to what portion of L-type calcium channels? the inner surface of the cell membrane Open channel blockade of dilt and verapamil result in? pronounced frequency depedence (works better on increased HR) Diltiazem is selective for inhibiting Ca channels where? In the SA/AV node and cardiac muscle