Pharmacology Regarding Cardiac Diseases |

 

Pharmacology Regarding Cardiac Diseases

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1. Review

This section provides a foundational understanding of the pathophysiology of cardiac diseases and the role of pharmacological agents in managing these conditions. It covers the types of cardiac diseases, their clinical manifestations, and the rationale for drug therapy, emphasizing the balance between efficacy and safety in treatment.

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2. Pharmacokinetics

Pharmacokinetics focuses on the absorption, distribution, metabolism, and excretion (ADME) of cardiac drugs:

• Absorption: Oral, intravenous, or sublingual routes affect drug onset. For example, nitroglycerin has rapid sublingual absorption.
• Distribution: Lipid-soluble drugs like beta-blockers easily cross membranes, impacting cardiac tissues.
• Metabolism: Most cardiac drugs are metabolized in the liver (e.g., statins).
• Excretion: Kidneys excrete many drugs, necessitating dose adjustments in renal impairment.

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3. Analgesics/Anti-inflammatory Agents

• Used for pain and inflammation in cardiac conditions like pericarditis or myocardial infarction.
• Examples: Aspirin, which also has an antiplatelet effect, and NSAIDs like ibuprofen.
• Nursing Role: Monitor for gastrointestinal side effects and bleeding risks.

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4. Antibiotics and Antiseptics

• Used to manage infections such as endocarditis or to prevent postoperative infections after cardiac surgery.
• Examples: Penicillins, cephalosporins, or vancomycin.
• Nursing Role: Administer antibiotics timely and observe for allergic reactions.

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5. Drug Reaction and Toxicity

• Cardiac drugs have narrow therapeutic ranges; toxicity can cause life-threatening events.
• Examples: Digoxin toxicity (manifested by arrhythmias, nausea, and visual disturbances) and beta-blocker overdose.
• Nursing Role: Monitor therapeutic drug levels and patient symptoms.

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6. Drugs Used in Cardiac Emergencies

• Examples:
  • Vasopressors: Epinephrine for cardiac arrest.
  • Antiarrhythmics: Amiodarone for ventricular arrhythmias.
  • Thrombolytics: Streptokinase for myocardial infarction.
• Nursing Role: Administer drugs as per ACLS protocols, monitor vital signs.

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7. Blood and Blood Components

• Used in anemias, blood loss, or to improve oxygenation in cardiac patients.
• Examples: Packed RBCs, platelets, and plasma.
• Nursing Role: Perform crossmatching, monitor for transfusion reactions.

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8. Cardiac Drug Classes

A. Antithrombolytic Agents:

• Prevent clot formation.
• Examples: Aspirin, clopidogrel.

B. Inotropic Agents:

• Increase myocardial contractility.
• Examples: Dobutamine, digoxin.

C. Beta-Blocking Agents:

• Reduce heart rate and oxygen demand.
• Examples: Metoprolol, atenolol.

D. Calcium Channel Blockers:

• Relax vascular smooth muscle and reduce heart workload.
• Examples: Amlodipine, diltiazem.

E. Vasoconstrictors:

• Increase blood pressure in hypotension.
• Examples: Norepinephrine.

F. Vasodilators:

• Relax blood vessels and lower BP.
• Examples: Nitroglycerin, hydralazine.

G. ACE Inhibitors:

• Reduce blood pressure by blocking angiotensin.
• Examples: Enalapril, lisinopril.

H. Anticoagulants:

• Prevent thrombus formation.
• Examples: Warfarin, heparin.

I. Antiarrhythmic Drugs:

• Treat irregular heartbeats.
• Examples: Amiodarone, lidocaine.

J. Antihypertensives:

• Lower blood pressure.
• Examples: Losartan, hydrochlorothiazide.

K. Diuretics:

• Remove excess fluid, reduce workload on the heart.
• Examples: Furosemide, spironolactone.

L. Sedatives and Tranquilizers:

• Reduce anxiety and sympathetic stimulation.
• Examples: Lorazepam, diazepam.

M. Digitalis:

• Enhances cardiac contractility.
• Example: Digoxin.

N. Antilipemics:

• Reduce cholesterol levels.
• Examples: Atorvastatin, rosuvastatin.

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9. Principles of Drug Administration

• Five Rights: Right patient, drug, dose, route, and time.
• Use aseptic techniques and adhere to protocols for IV infusions or injections.

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10. Role and Responsibilities of Nurses

• Monitor patients for drug effectiveness and adverse effects.
• Educate patients on drug regimens, side effects, and adherence.
• Report and document drug reactions promptly.
• Store drugs appropriately, ensuring safety and efficacy.

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11. Care of Drugs

• Proper storage per manufacturer guidelines (e.g., refrigeration).
• Regularly check expiry dates and dispose of expired drugs safely.
• Label drugs clearly and maintain an organized medication storage system.