Calcium Channel Blockers Practice Exam Questions and Correct Answers

What are the three main classes of calcium channel blocking drugs? 1. Dihydropyridine 2. Benzothiazepines 3. Phenylalkylamines What drug is the benzothiazepine prototype? Diltiazem What drug is the phenylakylamine prototype? Verapamil What is the common suffix used by the dihydropyridine class? -dipine What are the primary clinical uses for calcium channel blockers? 1. Hypertension 2. Angina 3. Arrhythmia (supraventricular) What arrhythmias are calcium channel blockers good at treating? 1. Atrial Flutter 2. Atrial Fibrillation 3. Paroxysmal Supraventricular Tachycardia What is the mechanism of contraction in cardiac myocytes? What about vascular smooth muscle? 1. Influx of calcium from extracellular space --> trigger release of calcium from smooth endoplasmic reticulum --> calcium binds to troponin C --> interaction between actin and myosin occurs --> contraction. 2. Smooth Muscle --> stimulate MLCK by binding calmodulin --> phosphorylation of myosin --> contraction. What type of channels do calcium blockers act on? 1. L-Type (voltage dependent) calcium channels found in the heart and vascular smooth muscle. What type of calcium channels are found in the SA node and AV node and are important in the upstroke of the action potential? 1. T-Type Calcium Channels (Transient) What stage of the action potential are L-type calcium channels important in? 1. Phase 2 - Plateau Phase What drugs are prototypes of the dihydropyridine class? 1. Nifedipine, Amlodipine, Felodipine, Nicardipine, Isradipine