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Pharmacology II Cardiac & Vascular. Kathy Plitnick RN PhD CCRN Georgia Baptist College of Nursing. Physiology of Circulation. Return of deoxygenated blood to the heart Enters the lungs to reoxygenated Ejected out of the left ventricle. Cardiac Glycosides. Positive Inotropes
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Pharmacology II Cardiac & Vascular Kathy Plitnick RN PhD CCRN Georgia Baptist College of Nursing
Physiology of Circulation • Return of deoxygenated blood to the heart • Enters the lungs to reoxygenated • Ejected out of the left ventricle
Cardiac Glycosides • Positive Inotropes • Increase contractility & CO • Improved renal perfusion • Increased GFR • Increased urine output • Slow onset of action
Digoxin – Prototype • Inhibits Na/K+ pump • Calcium remains intracellular longer • Improves contractility • Lowers heart rate • Treatment for At. Fib/Flutter, PSVT • Digitalization
Digoxin – Prototype • Side Effects • Bradycardia • Heart block • Toxic Effects • CNS & GI • Visual disturbances • Precipitated by low K+, Mg, & Ca+ levels • Antidote: Digibind • Therapeutic Level: 0.5-2.0 ng/ml
Digoxin – Prototype • Nursing • Assess apical pulse for 60 seconds • Hold if HR < 60, Call MD • Draw blood levels 6-8 hours after dose • Monitor drug levels, electrolytes • Teach patient to take own pulse • Monitor K+, Mag & Calcium
Cardiotonics • Inocor – Inamrinone • Primacor – Milrinone • Both given by continuous IV infusion • Dosages adjusted to maintain a CI > 2.0 • Heart Transplant candidates
Coronary Vasodilators • Nitrates: Nitroglycerin, Isordil • Relax arterial & venous smooth muscle • Primary effect on veins • Decrease myocardial work, O2 requirements • Improves perfusion during ischemia • Arterial dilatation
Nitrates • Routes • Sublingual • Oral • Ointment • Transdermal • Parenteral
Nitrates • Side Effects • Headache • Hypotension • Dizziness • Palpitations • Difficulty breathing • Chest pain
Nitrates • Nursing • IV infusion – frequent VS • Continuous cardiac monitoring • Maintain systolic BP > 90 mmHg • Sublingual • 3 tablets q 5 minutes • Call 911 if no relief • Continuous cardiac monitoring
Antidysrhythmic Agents • Terminate/prevent abnormal cardiac rhythms • Classified according to primary effect on action potential
Class I – Sodium Channel Blockers • Decrease influx of Na+ ions through fast channels during phase 0 • Prolongs absolute refractory period • Slow rate of spontaneous depolarization during phase 4 • Negative inotrope, chronotrope • Decrease myocardial O2 demand
Class IA – Quinidine • Also slows phase 3 repolarization • Prolong AP duration • Increases QRS & QT • Depress contractility • Give with food • Cardiac monitoring
Class IB – Lidocaine • Continuous IV for ventricular dysrhythmias • Weakens phase 4 • Decreases automaticity, AP duration • Raises V. Fib threshold • Biphasic half-life • Topical & local anesthetic • Lidocaine “crazies”
Class IC – Encainide, Flecainide, Propafenone • Slow conduction through His-Purkinje • Increase both PR & QRS • Increased mortality with Encainide & Flecainide
Class II – Beta Blockers • Cardioselective • Metoprolol • Atenolol • Acebutolol • Non-cardioselective • Propranolol – Prototype • Nadolol • Esmolol
Class III - Amiodarone • Slow rate of phase 3 repolarization • Increase effective refractory period • Treat atrial & ventricular dysrhythmias • Has characteristics of all 4 classes • Blocks potassium channels • Vasodilatory action
Amiodarone • Major Adverse Effects • Hypotension, bradycardia, AV block • Elevation of LFT’s • Proarrhythmic effect • Torsades • ARDS • Pulmonary fibrosis
Amiodarone • Nursing • Baseline pulmonary, LFT’s, CXR • Monitor VS, EKG • Assess pulse for strength, rate, regularity • Monitor for side effects • Nausea, fever, decreased appetite • Blue-gray discoloration of skin • Blurred vision
Amiodarone • Correct electrolyte imbalances • Check SaO2/ABG’s • Continuous cardiac monitoring • Central line for infusion
Class IV – Calcium Channel Blockers • Inhibit influx of calcium during phase 2 • Primarily in sinus & AV nodes, atrial tissue • Negative inotropic, chronotropic, dromotropic effects • Increases angina threshold
Verapamil (Calan) • Depresses sinus & AV node • Terminates SVT caused by AV nodal reentry • Controls ventricular rate in AFib/Flutter • Contraindicated in Sick Sinus Syndrome, advanced block, cardiogenic shock
Verapamil • Nursing • Administer slow > 2 minutes • Continuous EKG monitoring • Frequency VS • Avoid concomitant use of Beta Blockers
Diltiazem (Cardizem) • Fewer hypotensive side effects • Control of ventricular rate in atrial dysrhythmias • Rapid conversion of PSVT to NSR • Treatment of Angina • Initial bolus followed by continuous IV
Adenosine • Treatment of PSVT & diagnostic aid • Slows impulse formation in SA node & through AV node • Depresses LV function • Half-life less than 10 seconds ! • Monitor patient very closely • Given IV bolus • Monitor EKG, apical pulse, BP, respirations
Antihyperlipidemics • Definition of Hyperlipidemia • Can lipids be bad? • 3 Types of Agents Used • HMG CoA reductase inhibitors - Statins • Zocor, Mevacor, Pravachol • Block the synthesis of cholesterol in the liver • Decrease LDL, increase HDL • Fibric Acids • Lopid, Tricor • Decrease concentration of VLDL • Increase lipase – promotes VLDL catabolism
Antihyperlipidemics • Bile Acid Sequestrants • Questran, Welchol, Colestid • Lower LDL levels • Bind bile acids in intestine • Major Interaction • Increase effects of anticoagulants • Do not give with grapefruit juice
Antihyperlipidemics • Dietary corrections • Reduce fats, sugars & cholesterol • High fiber foods • Obtain baseline levels • Monitor GI effects • Increase water intake • Administer dose in evenings