Cardiac Medications Guide for NCLEX
Cardiac medications are among the most heavily tested pharmacology topics on the NCLEX. This guide covers the major classes of cardiac drugs including antihypertensives, antianginals, antiarrhythmics, heart failure medications, and anticoagulants. For each drug class, you will learn the mechanism of action, key nursing implications, critical side effects, patient teaching points, and the lab values that must be monitored for safe administration.
Learning Objectives
- ✓Identify the mechanism of action, nursing implications, and critical side effects for major cardiac medication classes
- ✓Apply safe medication administration principles including lab monitoring, vital sign parameters, and contraindications
- ✓Develop patient teaching plans for commonly prescribed cardiac medications
1. Antihypertensives: ACE Inhibitors, ARBs, Beta-Blockers, and Calcium Channel Blockers
ACE inhibitors (ending in -pril: lisinopril, enalapril, captopril) block the conversion of angiotensin I to angiotensin II, reducing vasoconstriction and aldosterone secretion. Key nursing concerns include a persistent dry cough (most common side effect), hyperkalemia (do not combine with potassium supplements or potassium-sparing diuretics without monitoring), angioedema (swelling of face, lips, tongue, a medical emergency), and first-dose hypotension. Monitor potassium and renal function (BUN, creatinine). Contraindicated in pregnancy. ARBs (ending in -sartan: losartan, valsartan) block angiotensin II receptors and produce similar effects to ACE inhibitors without the cough. They are used as an alternative when ACE inhibitor cough is intolerable. Same precautions regarding hyperkalemia and pregnancy. Beta-blockers (ending in -olol: metoprolol, atenolol, propranolol, carvedilol) decrease heart rate and blood pressure by blocking beta-adrenergic receptors. Hold if heart rate is below 60 bpm or systolic BP is below 100 mmHg. Never discontinue abruptly as this can cause rebound hypertension or angina. Beta-blockers mask the symptoms of hypoglycemia in diabetic patients (tachycardia, tremors) except for sweating. Contraindicated in asthma (non-selective beta-blockers cause bronchospasm). Calcium channel blockers (amlodipine, diltiazem, verapamil, nifedipine) relax vascular smooth muscle and decrease cardiac contractility. They reduce blood pressure and heart rate (diltiazem, verapamil) or primarily reduce blood pressure with less cardiac effect (amlodipine, nifedipine). Monitor for peripheral edema, constipation, and bradycardia. Avoid grapefruit juice as it increases drug levels. Verapamil and diltiazem should not be combined with beta-blockers due to excessive bradycardia risk.
Key Points
- •ACE inhibitors (-pril): watch for dry cough, hyperkalemia, angioedema, first-dose hypotension; monitor K+ and renal function
- •Beta-blockers (-olol): hold for HR below 60, never stop abruptly, mask hypoglycemia symptoms in diabetics, avoid in asthma
- •Calcium channel blockers: monitor for edema and bradycardia, avoid grapefruit juice, do not combine verapamil/diltiazem with beta-blockers
- •All antihypertensives: teach patients to rise slowly (orthostatic hypotension), do not skip doses, and report dizziness or syncope
2. Heart Failure Medications and Digoxin
Heart failure is treated with a combination of medications that reduce preload, afterload, and cardiac workload while improving contractility. The standard regimen includes ACE inhibitors (reduce afterload and prevent remodeling), beta-blockers (reduce heart rate and oxygen demand), diuretics (reduce preload and fluid overload), and in some cases digoxin (increase contractility). Loop diuretics (furosemide/Lasix, bumetanide) are the mainstay for managing fluid overload in heart failure. They block sodium and chloride reabsorption in the loop of Henle, producing potent diuresis. Monitor for hypokalemia (increases digoxin toxicity risk), hyponatremia, dehydration, ototoxicity (especially with IV push administration), and hypotension. Teach patients to weigh themselves daily and report a gain of 2 or more pounds overnight. Digoxin (Lanoxin) increases the force of cardiac contraction (positive inotrope) and decreases heart rate (negative chronotrope). Therapeutic level is 0.5-2.0 ng/mL. Check apical pulse for a full 60 seconds before administration; hold and notify the provider if heart rate is below 60 bpm in adults. Hypokalemia dramatically increases digoxin toxicity risk. Signs of toxicity include GI symptoms (nausea, vomiting, anorexia), visual disturbances (yellow-green halos around lights), and cardiac dysrhythmias. The antidote is digoxin immune Fab (Digibind). Spironolactone (Aldactone) is a potassium-sparing diuretic and aldosterone antagonist used in heart failure. It reduces mortality in severe HF. Unlike loop diuretics, it causes potassium retention (hyperkalemia risk). Do not combine with ACE inhibitors or ARBs without careful potassium monitoring. Also causes gynecomastia (breast enlargement) in males.
Key Points
- •Loop diuretics (furosemide): monitor for hypokalemia, ototoxicity, dehydration; daily weights to track fluid status
- •Digoxin: therapeutic 0.5-2.0 ng/mL, hold for HR below 60, check K+ (hypokalemia increases toxicity), antidote is Digibind
- •Digoxin toxicity triad: GI symptoms, yellow-green visual halos, cardiac dysrhythmias
- •Spironolactone: potassium-sparing (hyperkalemia risk), do not combine with ACE/ARBs without K+ monitoring, causes gynecomastia
3. Antianginals, Anticoagulants, and Antiplatelets
Nitroglycerin (NTG) is the first-line treatment for angina. It dilates coronary arteries and reduces preload through venous dilation. Sublingual NTG: give one tablet every 5 minutes for up to 3 doses. If chest pain is not relieved after the first dose, call 911. Check blood pressure before each dose and hold if systolic BP is below 90 mmHg. Contraindicated in patients who have taken phosphodiesterase-5 inhibitors (sildenafil/Viagra, tadalafil/Cialis) within 24-48 hours due to severe hypotension risk. Store in original dark glass container; replace every 6 months. A headache after taking NTG indicates the drug is working (vasodilation). Warfarin (Coumadin) inhibits vitamin K-dependent clotting factors. Monitor PT/INR; therapeutic INR is 2.0-3.0 (2.5-3.5 for mechanical heart valves). Antidote is vitamin K (phytonadione). Teach patients to maintain consistent vitamin K intake in the diet (green leafy vegetables), avoid drastic dietary changes, and report any unusual bleeding or bruising. Contraindicated in pregnancy. Heparin activates antithrombin III. Unfractionated heparin (UFH) is given IV and monitored with aPTT (goal 1.5-2.5x control). Low molecular weight heparin (enoxaparin/Lovenox) is given subcutaneously and does not require routine aPTT monitoring. Antidote for heparin is protamine sulfate. Monitor platelets for heparin-induced thrombocytopenia (HIT), which typically occurs 5-10 days after initiation. Aspirin and clopidogrel (Plavix) are antiplatelet agents that inhibit platelet aggregation. Aspirin 81-325 mg daily is used for cardiovascular risk reduction. Give chewable aspirin immediately for suspected MI. Both increase bleeding risk and should be held before surgery as directed.
Key Points
- •Nitroglycerin: SL every 5 min x 3 doses, hold for SBP below 90, contraindicated with PDE-5 inhibitors (Viagra), headache is expected
- •Warfarin: PT/INR monitoring (goal 2.0-3.0), antidote is vitamin K, maintain consistent dietary vitamin K, contraindicated in pregnancy
- •Heparin: aPTT monitoring for UFH (1.5-2.5x control), antidote is protamine sulfate, monitor for HIT (platelet drop at days 5-10)
- •Aspirin for MI: chewable 162-325 mg immediately; daily 81 mg for cardiovascular prophylaxis
High-Yield Facts
- ★ACE inhibitors and ARBs are both contraindicated in pregnancy due to teratogenic effects (fetal renal damage)
- ★Beta-blockers should never be stopped abruptly because rebound tachycardia and hypertensive crisis can occur
- ★The most common side effect of ACE inhibitors is a dry, nonproductive cough caused by bradykinin accumulation
- ★Nitroglycerin tablets should be stored in a dark glass container, replaced every 6 months, and cause a tingling or burning sensation under the tongue if potent
- ★Warfarin and heparin are often given together because warfarin takes 3-5 days to reach therapeutic effect
Practice Questions
1. A client is prescribed metoprolol 50 mg PO twice daily. Before administering the morning dose, the nurse assesses the client's vital signs: BP 108/68 mmHg, HR 54 bpm, RR 16. What is the appropriate nursing action? A) Administer the medication as prescribed. B) Hold the medication and notify the provider. C) Administer half the prescribed dose. D) Recheck the vital signs in 30 minutes.
2. A client taking warfarin has a lab result showing an INR of 4.8. The client is not currently bleeding. Which nursing action is the priority? A) Administer protamine sulfate IV. B) Hold the warfarin and notify the provider. C) Continue the current dose and recheck in 24 hours. D) Administer vitamin K 10 mg IV immediately.
FAQs
Common questions about this topic
The most frequently tested cardiac medications include: digoxin (hold for HR below 60, check potassium, toxicity signs), beta-blockers (hold for HR below 60, never stop abruptly), nitroglycerin (sublingual protocol, contraindicated with Viagra), warfarin (INR monitoring, vitamin K antidote), heparin (aPTT monitoring, protamine sulfate antidote), and ACE inhibitors (dry cough, hyperkalemia, angioedema). Know the nursing actions, monitoring parameters, and patient teaching for each.
Use the memory aid: WarfaRIN = INR (both share the letters R-I-N) and HepariN = PTT (the last letter N reminds you of PTT). Warfarin is monitored with PT/INR with a therapeutic goal of 2.0-3.0. Heparin (unfractionated) is monitored with aPTT with a therapeutic goal of 1.5-2.5 times the control value. Low molecular weight heparin (enoxaparin) does not require routine aPTT monitoring.