pharmacology ii cardiac & vascular

Pharmacology II Cardiac & VascularKathy 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

NursingAssess apical pulse for 60 secondsHold if HR < 60, Call MDDraw blood levels 6-8 hours after doseMonitor drug levels, electrolytesTeach patient to take own pulseMonitor K+, Mag & Calcium

Cardiotonics

Inocor – Inamrinone Primacor – Milrinone

Both given by continuous IV infusionDosages adjusted to maintain a CI > 2.0Heart Transplant candidates

Coronary Vasodilators

Nitrates: Nitroglycerin, IsordilRelax arterial & venous smooth musclePrimary effect on veinsDecrease myocardial work, O2 requirements

Improves perfusion during ischemiaArterial dilatation

Nitrates

RoutesSublingualOralOintmentTransdermalParenteral

Nitrates

Side EffectsHeadache HypotensionDizzinessPalpitationsDifficulty breathingChest pain

Nitrates

Nursing IV infusion – frequent VS

Continuous cardiac monitoring

Maintain systolic BP > 90 mmHgSublingual

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 repolarizationProlong 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

CardioselectiveMetoprololAtenololAcebutolol

Non-cardioselectivePropranolol – PrototypeNadololEsmolol

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 EffectsHypotension, bradycardia, AV blockElevation of LFT’sProarrhythmic effectTorsades ARDSPulmonary fibrosis

Amiodarone

NursingBaseline pulmonary, LFT’s, CXRMonitor VS, EKGAssess pulse for strength, rate, regularityMonitor 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

NursingAdminister slow > 2 minutesContinuous EKG monitoringFrequency VSAvoid 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 SequestrantsQuestran, Welchol, ColestidLower LDL levelsBind bile acids in intestine

Major Interaction Increase effects of anticoagulantsDo 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