Heart drugs video

Key Concepts of Cardiac Pharmacology

The primary goal of cardiac pharmacology is to manage fluid levels, reduce the workload of the heart, and enhance effective blood circulation. Understanding the mechanisms of various drug classes allows practitioners to make educated choices regarding patient treatments, contributing to improved health outcomes.

Drug Classifications and Their Effects

General Observations:

• Most cardiac drugs discussed primarily aim to lower blood pressure, reducing the strain on the heart and improving overall cardiovascular health.

• Digoxin is an exception: it primarily affects heart rate without altering blood pressure, making it a unique agent in heart failure management.

• NCLEX Tip: Pay attention to drug endings, as they often provide clues about their function and potential side effects.

Drug Classes

1. ACE Inhibitors and ARBs

   • Examples: ACE Inhibitors typically end in -pril (e.g., Lisinopril), while ARBs end in -sartan (e.g., Losartan).

   • Function: These medications effectively lower blood pressure without affecting heart rate.

   • Key Mechanism: They inhibit or block the Renin-Angiotensin-Aldosterone System (RAAS), leading to vasodilation and decreased fluid retention.

   • Side Effects:

     • ACE Inhibitors can cause a persistent cough and angioedema (swelling of the face and tongue).

     • Both classes carry a risk of hyperkalemia (high potassium levels), particularly in patients with renal impairment.

     • They are contraindicated in pregnancy due to risks to fetal development.

   • Monitoring: Prior to administration, check potassium levels and blood pressure.

2. Beta Blockers

   • Examples: These medications typically end in -lol (e.g., Atenolol, Metoprolol).

   • Function: They decrease both heart rate and blood pressure, making them beneficial in managing conditions like hypertension and heart failure.

   • Mechanism: Beta-blockers work by blocking beta-adrenergic receptors in the sympathetic nervous system, leading to negative chronotropic (reduced heart rate), dromotropic (decreased conduction speed), and inotropic (decreased force) effects.

   • Side Effects:

     • They can exacerbate respiratory conditions such as asthma/COPD due to bronchoconstriction.

     • Other side effects include bradycardia, hypotension, and masking symptoms of low blood sugar.

   • Monitoring: Assess heart rate and blood pressure before administration; withhold if heart rate is < 60 bpm or BP < 90/100 mmHg.

3. Calcium Channel Blockers (CCBs)

   • Examples: Most commonly end in -pine (e.g., Amlodipine), and include others such as Diltiazem and Verapamil.

   • Function: They lower both heart rate and blood pressure by relaxing the smooth muscles of blood vessels, leading to vasodilation.

   • Mechanism: By blocking calcium from entering heart and vascular smooth muscle cells, CCBs cause a decrease in muscle contraction, resulting in lowered blood pressure.

   • Side Effects:

     • Possible side effects include cardiovascular depression, hypotension, and headaches.

     • Caution is advised when administering to patients with already low heart rate or blood pressure.

4. Digoxin

   • Property: This medication increases myocardial contractility while decreasing heart rate, classified as a positive inotropic and negative chronotropic agent. It's commonly used in treating systolic heart failure and atrial fibrillation.

   • Toxicity Risks: Symptoms of toxicity include visual disturbances (e.g., halos around lights), gastrointestinal issues (nausea, vomiting), and arrhythmias, particularly in the presence of hypokalemia (low potassium levels). Requires careful monitoring of pulse and serum drug levels, with an action to hold if pulse < 60 bpm and to avoid levels > 2.0 ng/mL (toxic).

5. Vasodilators

   • Common Agent: Nitroglycerin, which is used for the management of angina and acute heart failure episodes.

   • Function: These drugs primarily reduce preload and afterload, lowering blood pressure and improving oxygen delivery to cardiac tissue.

   • Monitoring: Always check blood pressure before administration and monitor for signs of hypotension; contraindicated for patients taking erectile dysfunction medications (e.g., Viagra) due to risk of severe hypotension.

6. Diuretics

   • Types: These include potassium-wasting (e.g., Furosemide) and potassium-sparing diuretics (e.g., Spironolactone).

   • Function: Diuretics are utilized to reduce excess fluid, which is critical in managing heart failure and certain renal conditions.

   • Monitoring: Regularly assess blood pressure, kidney function tests (BUN, creatinine), and potassium levels. Rapid administration can risk ototoxicity, particularly with loop diuretics.

   • Patient Education: Advise patients to consume potassium-rich foods while on potassium-wasting diuretics and to avoid high potassium intake when on potassium-sparing types.

Nursing Considerations and Tips

• Monitoring: Always assess vital signs before administering medications affecting heart and blood pressure to prevent adverse events.

• Positioning: Instruct patients to change positions gradually to prevent orthostatic hypotension.

• Patient Education: Inform patients about lifestyle modifications, including dietary changes (e.g., reducing sodium intake) and ensuring adequate hydration.

• Emergency Protocols: Be prepared to intervene during electrolyte imbalances, blood pressure crises, and signs of drug toxicity, particularly in vulnerable populations such as the elderly and those with renal impairment.

Conclusion

Understanding pharmacology is essential for ensuring patient safety and effective nursing practice. Armed with this knowledge, nurses can better prepare for the NCLEX and make informed clinical decisions that enhance patient care.