Guide to Common Cardiac Medications

Cardiac Pharmacology Overview

Cardiac medications manage cardiovascular disease. Acute resuscitation and chronic heart failure management require precise administration. Minor errors can cause hemodynamic instability. This guide categorizes cardiac drugs by mechanism, indication, and nursing implication, providing a framework for safe clinical practice.

Hemodynamic interplay between preload, afterload, and contractility determines treatment efficacy. Refer to the American Heart Association (AHA) for clinical guidelines.

ACE Inhibitors

Suffix: -pril (Lisinopril, Enalapril)
Mechanism: Blocks Angiotensin I conversion to Angiotensin II (vasoconstrictor). Causes vasodilation and reduces aldosterone (lowers sodium/water retention).

• Indications: Hypertension, Heart Failure, Diabetic Nephropathy.
• Nursing: Monitor BP (first-dose hypotension), Potassium (hyperkalemia), renal function.
• Patient Ed: Report dry cough or angioedema. Avoid potassium substitutes.

Angiotensin II Receptor Blockers (ARBs)

Suffix: -sartan (Losartan, Valsartan)
Mechanism: Directly blocks Angiotensin II receptors. Prevents vasoconstriction and aldosterone release.

• Indications: HTN, HF, intolerance to ACE inhibitors.
• Differentiation: No bradykinin accumulation means no dry cough.
• Nursing: Monitor BP, renal function, potassium.

Beta-Adrenergic Blockers

Suffix: -olol (Metoprolol, Atenolol, Carvedilol)
Mechanism: Blocks Beta-1 (heart) and Beta-2 (lungs) receptors. Reduces heart rate, contractility, and AV conduction.

• Indications: HTN, Angina, Heart Failure, Afib.
• Nursing: Hold if Apical Pulse < 60 or SBP < 90. Use cardio-selective agents (Metoprolol) in asthma/COPD.
• Patient Ed: Do not stop abruptly (rebound HTN risk). Masks hypoglycemia symptoms.

Calcium Channel Blockers (CCBs)

Suffix: -pine (Amlodipine) or non-dihydropyridines (Diltiazem, Verapamil).
Mechanism: Inhibits calcium influx, causing arterial vasodilation and reduced conduction.

• Indications: HTN, Angina, Rapid Afib (Diltiazem).
• Nursing: Monitor for reflex tachycardia, peripheral edema.
• Patient Ed: Avoid grapefruit juice. Change positions slowly.

Diuretics

Reduce blood volume via renal excretion.

Loop Diuretics

Examples: Furosemide (Lasix).
Action: Inhibits Na/Cl reabsorption in Loop of Henle. Potent diuresis.
Risk: Hypokalemia, Ototoxicity (rapid IV push).

Thiazide Diuretics

Examples: Hydrochlorothiazide (HCTZ).
Action: Inhibits Na reabsorption in distal tubule. First-line for HTN.
Risk: Hypokalemia, Hyperglycemia.

Potassium-Sparing Diuretics

Examples: Spironolactone.
Action: Blocks aldosterone. Weak diuretic, retains potassium.
Risk: Hyperkalemia.

Lipid-Lowering Agents (Statins)

Suffix: -statin (Atorvastatin, Rosuvastatin)
Mechanism: Inhibits HMG-CoA reductase, reducing cholesterol synthesis. Decreases LDL, increases HDL.

• Indications: Hyperlipidemia, CAD prevention.
• Nursing: Monitor Liver Function Tests (LFTs).
• Patient Ed: Report muscle pain (Rhabdomyolysis risk). Take in evening.

Vasopressors and Inotropes

Critical care agents for shock management.
Norepinephrine (Levophed): Potent vasoconstrictor (Alpha-1). First-line for septic shock.
Epinephrine: Increases HR/contractility and vasoconstriction. Cardiac arrest, anaphylaxis.
Dopamine: Dose-dependent effects. Renal (low), Cardiac (med), Vasopressor (high).
Dobutamine: Inotrope. Increases contractility. Used in heart failure.
Nursing: Central line preferred (necrosis risk). Titrate to MAP > 65. Continuous monitoring.

Anticoagulants and Antiplatelets

Prevent clot formation.

Anticoagulants (Venous)

Warfarin: Vitamin K antagonist. Monitor PT/INR (2.0-3.0). Antidote: Vitamin K.
Heparin: Activates Antithrombin III. Monitor PTT. Antidote: Protamine Sulfate.
DOACs (Apixaban): Factor Xa inhibitors. No routine monitoring.

Antiplatelets (Arterial)

Aspirin, Clopidogrel: Prevent aggregation. MI/Stroke prophylaxis. Monitor GI bleeding.

Nitrates (Vasodilators)

Examples: Nitroglycerin.
Mechanism: Relaxes smooth muscle. Dilates veins (decreased preload) and arteries (decreased afterload).
Safety: Contraindicated with Sildenafil (fatal hypotension). Wear gloves with patches.

Antiarrhythmics

Digoxin: Increases contractility, decreases HR.
Toxicity: Halos, nausea, bradycardia. Monitor levels and Potassium.
Amiodarone: K+ channel blocker. Used for VT/VF/Afib.
Safety: Pulmonary toxicity, thyroid dysfunction. Long half-life.

FAQs: Cardiac Pharmacology

Conclusion

Cardiac medications require respect. Mastering ACE inhibitors, beta-blockers, and anticoagulants prevents adverse events. Verify parameters before administration and educate patients on toxicity signs.