Cardiac Medications Review

CARDIAC MEDICATIONS STUDY NOTES

ANTICOAGULANTS

  • Purpose: Prevent the formation of blood clots.

  • Uses: Indicated for patients at high risk of myocardial infarction (MI), stroke, or deep vein thrombosis (DVT). Specific conditions include:

    • Atrial Fibrillation

    • Mechanical Heart Valves

    • Stents

    • Decreased Mobility

  • Precautions: Major focus on safety to prevent bleeding, which may manifest as:

    • Gums

    • Nose

    • Urine

    • Bowel movements

    • Joints

    • Bruising

  • Patient Education:

    • Use a soft bristle toothbrush and electric razors to minimize cuts.

    • Use waxed dental floss.

    • Limit needle sticks; opt for small bore needles.

    • After needle sticks, apply extended pressure.

ORAL ANTICOAGULANTS: RISK PREVENTION

  • Warfarin:

    • Mechanism: Blocks vitamin K dependent clotting factors.

    • Monitoring: Prothrombin Time (PT) / International Normalized Ratio (INR) target range is 2-3.

    • Antidote: Phytonadione (vitamin K)

    • Administered orally if high INR without bleeding.

    • For active bleeding or critically high INR, administer IV vitamin K.

  • Nursing Considerations:

    • Dietary teaching: Be mindful of vitamin K rich foods; avoid sudden diet changes.

    • Ensure follow-up and laboratory appointments are kept.

    • Considerations for double coverage medications.

  • Direct Acting Oral Anticoagulants (DOACs):

    • Examples: Rivaroxaban, Apixaban, Dabigatran.

    • Pros: Less severe bleeding events, no required lab monitoring.

    • Cons: Expensive, difficult to determine effectiveness, lack of direct antidote.

    • Reversal Agents: Adexanet alfa (for rivaroxaban), Praxbind (for dabigatran).

INJECTABLE ANTICOAGULANTS

  • Heparin:

    • Uses: Prevention and treatment of clots. Note that heparin does not dissolve clots but prevents further clotting.

    • Antidote: Protamine sulfate.

    • Monitoring: Partial Thromboplastin Time (PTT) should be 1.5 to 2.5 times the baseline, typically 60 seconds to 90-120 seconds.

    • Nursing Considerations:

    • Dosing based on weight for IV or subcutaneous administration with a loading bolus and continuous infusion.

    • Verify calculations and dosing with a second nurse.

  • Enoxaparin (Lovenox):

    • Indicated for: DVT prophylaxis post-operatively or for patients with decreased mobility.

    • Nursing Considerations:

    • Dosing is weight-based for subcutaneous administration.

    • Ensure air bubble is present when injecting into the abdomen.

ANTIPLATELET DRUGS

  • Indications: For patients at risk of myocardial infarction and stroke.

  • Clopidogrel:

    • Typical dose for active MI is 300 mg.

  • Aspirin:

    • Standard dose is 81 mg per day.

    • Monitor for salicylate toxicity, including:

    • Nausea/Vomiting

    • Diaphoresis

    • Tinnitus.

    • Assess for allergy to tartrazine (yellow dye).

    • Nursing Considerations:

    • Bleeding precautions are paramount.

    • Discourage concurrent use with NSAIDs.

THROMBOLYTICS (FIBRINOLYTICS)

  • Examples: Alteplase (tPA), Streptokinase, Reteplase, Tenecteplase.

  • Function: Medications that break down clots.

    • Indications include ischemic stroke, myocardial infarction (MI), and pulmonary embolism (PE).

  • Nursing Considerations:

    • Assess the type of stroke carefully before administration.

    • Significant risk of bleeding events primarily during the first 24 hours post-administration; monitor closely.

    • Conduct neurological checks.

    • Apply bleeding precautions and maintain strict bedrest.

    • Avoid invasive procedures and ensure the patient is in an ICU setting.

DRUGS FOR HYPERTENSION

  • Categories:

    • Antihypertensives include:

    • Diuretics

    • Drugs affecting the Renin-Angiotensin-Aldosterone System (RAAS)

    • ACE inhibitors

    • Angiotensin receptor blockers (ARBs)

    • Calcium channel blockers

    • Beta blockers and alpha-blockers

    • Vasodilators

  • General Considerations for Antihypertensives (especially if on multiple):

    • Assess blood pressure before administration.

    • Hold medication and notify physician if systolic BP is <90 mmHg.

    • Watch for symptoms of first-dose hypotension and prevent orthostatic hypotension.

    • Provide patient education on symptoms including dizziness and lightheadedness.

DIURETICS

  • Mechanism: Diuretics reduce blood pressure through fluid reduction.

  • Thiazide Diuretics: Hydrochlorothiazide (HCTZ)

    • Functions primarily through kidney actions.

    • Risk of hypokalemia.

  • Other Diuretics:

    • Furosemide (Loop): Available in IV, PO, or IM forms, associated with tinnitus.

    • Spironolactone: Can cause gynecomastia.

    • Assessment of Effectiveness: Assess for dehydration and electrolyte issues; encourage foods high in potassium (K+).

    • Consider potassium supplementation if necessary.

RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM (RAAS)

  • Components:

    • Renin is secreted by the kidneys and acts on angiotensinogen to begin the cascade:

    • Angiotensin I is converted to Angiotensin II.

    • ACE inhibitors work at this conversion point.

    • Angiotensin II promotes the release of aldosterone, which causes vasoconstriction and sodium reabsorption.

    • Angiotensin Receptor Blockers (ARBs): Block angiotensin II receptors, preventing its effects.

RAAS DRUGS: VASODILATION AND DECREASING WORKLOAD

  • ACE Inhibitors: End in “-pril” (e.g., Benazepril, Captopril, Enalapril, Lisinopril).

    • Main effects include vasodilation and decreasing workload, essential for managing heart failure.

    • Side Effect: Can cause a dry, hacky cough. Recommendations include using antitussives or switching to ARBs if necessary.

  • ARBs: End in “-sartan” (e.g., Losartan, Valsartan).

    • Prevent vasoconstriction and decrease ventricular workload.

  • Common Side Effects (for both):

    • Angioedema

    • Hyperkalemia

    • Contraindicated in Pregnancy

CALCIUM CHANNEL BLOCKERS

  • Indications: Used for hypertension, angina, and tachyarrhythmias.

    • Common Agents: Amlodipine, Nifedipine, Nicardipine.

  • Mechanism: Results in arterial vasodilation, lowering BP and improving coronary blood flow.

  • Effects:

    • Slows SA node activity and helps in managing tachyarrhythmias like supraventricular tachycardia (SVT) and atrial fibrillation (A-fib).

  • Considerations:

    • Contraindicated with H2 blockers and grapefruit juice due to increased risk of toxicity.

    • Special care must be taken to monitor for bradycardia and peripheral edema.

BETA ADRENERGIC BLOCKERS

  • Mechanism: These block the sympathetic nervous system, inducing vasodilation and reduced heart rate.

  • Uses: Effective in treating heart failure, angina, and tachyarrhythmias.

  • Notable Medications: Examples include Atenolol, Carvedilol, Metoprolol, and Propranolol (the latter being non-selective and affecting both B1 and B2 receptors).

  • Cautions:

    • Monitor heart rate; hold if <60 bpm.

    • Use cautiously in diabetics and asthmatics as they may mask signs of hypoglycemia and increase the risk of asthma attacks.

  • Adverse Effects: Can cause bradycardia and bronchospasms; the antidote for overdose is glucagon.

CARDIAC GLYCOSIDES

  • Medications: Primary example is Digoxin.

  • Function: Increases myocardial contractility while decreasing heart rate, allowing ventricles to fill more effectively and increasing stroke volume and cardiac output.

  • Nursing Considerations:

    • Always assess apical pulse for one minute before administration.

    • Monitor for signs of digoxin toxicity including nausea, vomiting, anorexia, blurry vision, and visual disturbances (halos).

    • Monitor serum digoxin and potassium levels, considering electrolyte balance, especially regarding furosemide use.

    • Antidote for toxicity: Digibind.

NITRATES

  • Function: Promote vasodilation, enhancing coronary blood flow.

  • Acute Medications: Nitroglycerin is used for immediate treatment of angina, myocardial infarction, and hypertensive emergencies.

  • Routes of Administration: Available in tablet, spray, ointment, patch, or IV forms; nursing staff should wear gloves while administering.

  • Preventative Medication: Isosorbide mononitrate is a long-acting nitrate used to prevent angina.

  • Nursing Considerations:

    • Monitor blood pressure closely.

    • Inquire about use of phosphodiesterase type 5 (PDE-5) inhibitors due to potential for adverse effects.

    • Educate patients on correct use at home, noting that common side effects include headaches and light sensitivity.

MEDICATIONS FOR DYSRHYTHMIAS

  • Bradyarrhythmias:

    • Epinephrine: Increases blood pressure and heart rate. Used for treating bradycardia, ventricular fibrillation (V-fib), pulseless ventricular tachycardia (V-tach), pulseless electrical activity (PEA), and asystole.

    • Atropine: IV medication utilized for symptomatic bradycardia.

  • Tachyarrhythmias:

    • Adenosine: Acts as a “chemical cardioverter,” primarily used for supraventricular tachycardia (SVT). Administer as a rapid IV push followed by a rapid 20 mL flush; requires larger bore IV access.

    • Amiodarone: Used for ventricular tachyarrhythmias, A-fib with rapid ventricular response (RVR), V-tach, and V-fib; can be given IV or orally.

ANTI-LIPIDEMIC DRUGS: STATINS

  • Function: Statins interfere with cholesterol synthesis in the body.

  • Common Side Effects:

    • Gastrointestinal upset

    • Myopathy

    • Rhabdomyolysis

    • Monitoring of liver function is necessary.

  • Examples of Statins:

    • Atorvastatin (Lipitor)

    • Rosuvastatin (Crestor)

    • Simvastatin (Zocor)