The cardiovascular system, comprising the heart and blood vessels, is responsible for circulating blood throughout the body, delivering oxygen and nutrients, and removing waste products. Medications acting on the cardiovascular system are among the most commonly prescribed drugs, used to treat a wide range of conditions such as hypertension, heart failure, arrhythmias, and coronary artery disease.

Understanding these medications is crucial for nurses to safely administer them, monitor for therapeutic effects and adverse reactions, and educate patients on their importance and proper use.

This lesson will cover some of the major classes of medications used to affect the cardiovascular system.

1. Medications for Hypertension (High Blood Pressure)

Hypertension is a major risk factor for heart disease, stroke, and kidney disease. Antihypertensive medications work through various mechanisms to lower blood pressure.

a. Diuretics

Diuretics increase the excretion of sodium and water by the kidneys, reducing blood volume and consequently lowering blood pressure. They are often used as first-line treatment for hypertension.

• Thiazide Diuretics: (e.g., Hydrochlorothiazide – HCTZ)

  • Mechanism: Inhibit sodium and chloride reabsorption in the distal convoluted tubule.

  • Uses: Hypertension, mild to moderate edema.

  • Side Effects: Hypokalemia (low potassium), hyponatremia (low sodium), hyperglycemia (high blood sugar), hyperuricemia (high uric acid), dizziness, photosensitivity.

  • Nursing Implications: Monitor blood pressure, heart rate, I&O, and electrolytes (especially potassium). Educate patients on signs of hypokalemia (muscle weakness, cramps) and the importance of potassium-rich foods or supplements if prescribed. Advise on taking the medication in the morning to prevent nocturia.

• Loop Diuretics: (e.g., Furosemide, Bumetanide)

  • Mechanism: Inhibit sodium and chloride reabsorption in the loop of Henle, the most potent diuretics.

  • Uses: More severe hypertension, edema associated with heart failure, renal disease, or hepatic disease.

  • Side Effects: Significant hypokalemia, hyponatremia, hypocalcemia, ototoxicity (hearing damage, especially with rapid IV administration), dehydration, dizziness.

  • Nursing Implications: Monitor blood pressure, heart rate, I&O, daily weight, and electrolytes closely. Administer IV doses slowly. Educate on signs of electrolyte imbalance and dehydration.

• Potassium-Sparing Diuretics: (e.g., Spironolactone, Amiloride)

  • Mechanism: Act on the collecting duct to inhibit sodium reabsorption and potassium excretion (Spironolactone also blocks aldosterone).

  • Uses: Hypertension (often in combination with other diuretics), heart failure, edema.

  • Side Effects: Hyperkalemia (high potassium), especially when used alone or with other potassium-raising drugs. Spironolactone can cause gynecomastia.

  • Nursing Implications: Monitor blood pressure and potassium levels carefully. Advise patients to avoid potassium-rich foods and potassium supplements unless directed by the provider.

b. Beta-Blockers

Beta-blockers block the effects of adrenaline (epinephrine) and noradrenaline on beta-adrenergic receptors, primarily in the heart and blood vessels.

• Selective Beta-1 Blockers: (e.g., Metoprolol, Atenolol) Primarily block beta-1 receptors in the heart.

• Non-Selective Beta-Blockers: (e.g., Propranolol) Block both beta-1 and beta-2 receptors (beta-2 receptors are found in the lungs and blood vessels).

  • Mechanism: Decrease heart rate, reduce myocardial contractility, and lower renin release, leading to decreased blood pressure. Non-selective beta-blockers can also cause bronchoconstriction.

  • Uses: Hypertension, angina pectoris, arrhythmias, heart failure (certain types), post-myocardial infarction, migraine prophylaxis.

  • Side Effects: Bradycardia (slow heart rate), hypotension, fatigue, dizziness, depression, bronchospasm (especially with non-selective in patients with asthma/COPD), masking of hypoglycemia symptoms in diabetics.

  • Nursing Implications: Monitor blood pressure and heart rate before administration. Do not administer if heart rate is below 60 bpm or blood pressure is low (follow specific parameters). Educate patients not to stop taking the medication abruptly. Advise diabetic patients to monitor blood sugar closely. Assess for respiratory difficulties in patients with lung conditions.

c. Angiotensin-Converting Enzyme (ACE) Inhibitors

ACE inhibitors block the enzyme that converts angiotensin I to angiotensin II, a potent vasoconstrictor.

• (e.g., Lisinopril, Enalapril, Ramipril)

  • Mechanism: Block the production of angiotensin II, leading to vasodilation and reduced aldosterone secretion (which reduces sodium and water retention). This lowers blood pressure and reduces the workload on the heart.

  • Uses: Hypertension, heart failure, post-myocardial infarction, diabetic nephropathy.

  • Side Effects: Dry cough (common), angioedema (rare but serious swelling of face, tongue, throat), hyperkalemia, fatigue, dizziness, renal impairment.

  • Nursing Implications: Monitor blood pressure and potassium levels. Assess for cough and signs of angioedema. Educate patients to report these side effects immediately. Avoid in pregnancy.

d. Angiotensin II Receptor Blockers (ARBs)

ARBs block angiotensin II from binding to its receptors in blood vessels and other tissues.

• (e.g., Losartan, Valsartan, Candesartan)

  • Mechanism: Block the effects of angiotensin II, leading to vasodilation and reduced aldosterone secretion. Similar effects to ACE inhibitors but work at a different point in the pathway.

  • Uses: Hypertension, heart failure, diabetic nephropathy (often used if ACE inhibitors are not tolerated, e.g., due to cough).

  • Side Effects: Dizziness, fatigue, hyperkalemia, renal impairment. Less likely to cause cough or angioedema than ACE inhibitors.

  • Nursing Implications: Monitor blood pressure and potassium levels. Avoid in pregnancy.

e. Calcium Channel Blockers (CCBs)

CCBs block the movement of calcium into smooth muscle cells of blood vessels and heart muscle cells.

• Dihydropyridines: (e.g., Amlodipine, Nifedipine) Primarily affect blood vessels, causing vasodilation.

• Non-Dihydropyridines: (e.g., Verapamil, Diltiazem) Affect both blood vessels and the heart, slowing heart rate and reducing contractility.

  • Mechanism: Cause vasodilation (lowering blood pressure) and/or decrease heart rate and contractility.

  • Uses: Hypertension, angina pectoris, certain arrhythmias (non-dihydropyridines).

  • Side Effects:

    • Dihydropyridines: Peripheral edema (swelling in ankles/feet), headache, flushing, dizziness.

    • Non-Dihydropyridines: Bradycardia, constipation (especially Verapamil), dizziness, heart block.

  • Nursing Implications: Monitor blood pressure and heart rate. Assess for peripheral edema. Educate on potential side effects. Avoid grapefruit juice with some CCBs as it can increase drug levels.

f. Alpha-Blockers

Alpha-blockers block alpha-adrenergic receptors in blood vessels, causing vasodilation.

• (e.g., Prazosin, Terazosin, Doxazosin)

  • Mechanism: Block alpha-1 receptors in smooth muscle of blood vessels, leading to relaxation and vasodilation.

  • Uses: Hypertension (often used in combination), benign prostatic hyperplasia (BPH).

  • Side Effects: Orthostatic hypotension (dizziness upon standing), headache, palpitations.

  • Nursing Implications: Monitor blood pressure, especially when the patient changes position (lying, sitting, standing). Educate patients on the risk of dizziness and how to minimize it (change positions slowly). First dose is often given at bedtime to reduce the risk of “first-dose phenomenon” (marked orthostatic hypotension).

2. Medications for Heart Failure

Heart failure is a condition where the heart cannot pump enough blood to meet the body’s needs. Medications aim to improve the heart’s pumping ability, reduce fluid overload, and decrease the workload on the heart. Many antihypertensive medications (ACE inhibitors, ARBs, Beta-blockers, diuretics) are also used to treat heart failure.

a. Digoxin

A cardiac glycoside that increases the force of myocardial contraction.

• Mechanism: Inhibits the sodium-potassium pump in heart muscle cells, leading to increased intracellular calcium and stronger contractions. Also slows heart rate and conduction through the AV node.

• Uses: Heart failure (to improve symptoms and exercise tolerance), certain supraventricular arrhythmias (like atrial fibrillation) to control ventricular rate.

• Side Effects: Digoxin toxicity (narrow therapeutic range). Early signs include nausea, vomiting, anorexia, fatigue, visual disturbances (yellow/green halos), bradycardia, arrhythmias.

• Nursing Implications: Monitor apical pulse for a full minute before administration. Do not administer if pulse is below 60 bpm (check specific parameters). Monitor digoxin blood levels. Monitor potassium levels (hypokalemia increases the risk of digoxin toxicity). Educate patients on signs of toxicity and when to report them.

b. Nitrates

Cause vasodilation, primarily of veins, reducing preload (the amount of blood returning to the heart).

• (e.g., Nitroglycerin, Isosorbide dinitrate, Isosorbide mononitrate)

  • Mechanism: Converted to nitric oxide, a potent vasodilator. Reduces venous return to the heart, decreasing ventricular filling pressure and workload. Also causes some arterial dilation, improving blood flow.

  • Uses: Angina pectoris (chest pain due to reduced blood flow to the heart muscle), heart failure (to reduce congestion).

  • Side Effects: Headache (common, often severe), dizziness, hypotension, flushing, reflex tachycardia.

  • Nursing Implications: Monitor blood pressure and heart rate. Educate patients on proper administration (sublingual for acute angina, transdermal patch, ointment, or oral for prophylaxis). Advise on storing nitroglycerin properly (away from light and heat, in its original container). Educate on seeking medical attention if chest pain is not relieved by nitroglycerin.

3. Medications for Arrhythmias (Irregular Heartbeats)

Antiarrhythmic medications suppress abnormal electrical activity in the heart. They are classified into different classes based on their effects on cardiac action potentials. This is a complex group of drugs with significant risks.

• Class I (Sodium Channel Blockers): (e.g., Lidocaine, Procainamide, Flecainide)

• Class II (Beta-Blockers): (e.g., Propranolol, Esmolol)

• Class III (Potassium Channel Blockers): (e.g., Amiodarone, Sotalol)

• Class IV (Calcium Channel Blockers): (e.g., Verapamil, Diltiazem)

• Other: (e.g., Adenosine, Digoxin)

• Mechanism: Vary depending on the class, but generally alter ion movement across cardiac cell membranes to stabilize the heart rhythm.

• Uses: Treat or prevent various supraventricular and ventricular arrhythmias.

• Side Effects: Can cause new or worsen existing arrhythmias (proarrhythmia), bradycardia, hypotension, dizziness, and specific side effects depending on the drug (e.g., pulmonary toxicity, thyroid problems with Amiodarone).

• Nursing Implications: Continuous cardiac monitoring is often required, especially when initiating therapy. Monitor vital signs closely. Assess for signs of new or worsening arrhythmias. Monitor for specific side effects of the prescribed drug. Educate patients on the importance of taking medications as prescribed and reporting any new symptoms.

4. Medications Affecting Blood Clotting

These medications are used to prevent or treat blood clots, which can cause serious cardiovascular events like stroke, heart attack, and pulmonary embolism.

a. Antiplatelet Agents

Prevent platelets from clumping together to form a clot.

• (e.g., Aspirin, Clopidogrel, Ticagrelor)

  • Mechanism: Inhibit platelet aggregation through different pathways.

  • Uses: Prevent arterial clots in patients with a history of stroke, TIA, heart attack, or peripheral artery disease.

  • Side Effects: Increased risk of bleeding, gastrointestinal upset.

  • Nursing Implications: Monitor for signs of bleeding (bruising, petechiae, blood in stool/urine). Educate patients on the increased risk of bleeding and to report any unusual bleeding. Advise caution with activities that could cause injury.

b. Anticoagulants

Prevent or slow down the clotting process by interfering with clotting factors.

• Warfarin: (Oral)

  • Mechanism: Inhibits Vitamin K-dependent clotting factors.

  • Uses: Prevent venous clots (DVT, PE), prevent clots in atrial fibrillation, mechanical heart valves.

  • Side Effects: Increased risk of bleeding. Requires regular monitoring of INR (International Normalized Ratio) to ensure therapeutic levels.

  • Nursing Implications: Monitor INR closely. Educate patients on the importance of regular blood tests, the risk of bleeding, and interactions with Vitamin K-rich foods (consistent intake is key). Advise on avoiding activities that could cause injury. Many drug interactions.

• Heparin: (Injectable – IV or Subcutaneous)

  • Mechanism: Enhances the activity of antithrombin, which inactivates clotting factors.

  • Uses: Treat acute DVT/PE, prevent clots in certain situations (e.g., surgery, immobility), acute coronary syndromes.

  • Side Effects: Increased risk of bleeding, Heparin-Induced Thrombocytopenia (HIT – a serious immune reaction causing low platelets and increased clotting risk). Requires monitoring of aPTT (activated partial thromboplastin time).

  • Nursing Implications: Monitor aPTT and platelet count. Assess for signs of bleeding. Administer subcutaneous injections properly (do not rub the site).

• Low Molecular Weight Heparins (LMWHs): (e.g., Enoxaparin – Lovenox)

  • Mechanism: Similar to heparin but with a more predictable effect.

  • Uses: Prevent and treat DVT/PE, bridging therapy with warfarin. Administered subcutaneously.

  • Side Effects: Increased risk of bleeding, less risk of HIT than unfractionated heparin.

  • Nursing Implications: Monitor for signs of bleeding. Educate on proper subcutaneous injection technique.

• Direct Oral Anticoagulants (DOACs): (e.g., Dabigatran, Rivaroxaban, Apixaban)

  • Mechanism: Directly inhibit specific clotting factors (thrombin or Factor Xa).

  • Uses: Prevent stroke in atrial fibrillation, treat and prevent DVT/PE. Do not require regular INR monitoring (though specific tests may be used in certain situations).

  • Side Effects: Increased risk of bleeding.

  • Nursing Implications: Educate patients on the importance of taking the medication exactly as prescribed and not missing doses. Advise on the risk of bleeding and to report any unusual bleeding. Fewer drug and food interactions compared to warfarin, but still important to check.

5. Medications for Hyperlipidemia (High Cholesterol)

These medications are used to lower elevated levels of cholesterol and triglycerides in the blood, reducing the risk of atherosclerosis and cardiovascular disease.

• Statins: (e.g., Atorvastatin, Simvastatin, Rosuvastatin)

  • Mechanism: Inhibit an enzyme in the liver that is essential for cholesterol synthesis.

  • Uses: Lower LDL (“bad”) cholesterol, reduce the risk of heart attack and stroke.

  • Side Effects: Muscle pain (myalgia) or weakness (myopathy), liver enzyme elevation, gastrointestinal upset. Serious muscle breakdown (rhabdomyolysis) is rare but serious.

  • Nursing Implications: Monitor liver function tests. Educate patients to report any unexplained muscle pain or weakness. Administer some statins in the evening as cholesterol synthesis is higher at night. Avoid grapefruit juice with some statins.

• Other Lipid-Lowering Agents: (e.g., Ezetimibe, Fibrates, Niacin, PCSK9 Inhibitors) Used in combination with or as alternatives to statins.

Nursing Considerations Across Cardiovascular Medications

• Monitor Vital Signs: Always monitor blood pressure and heart rate before administering many cardiovascular medications.

• Assess for Therapeutic Effect: Monitor for improvement in symptoms (e.g., lower blood pressure, reduced edema, decreased chest pain, stable heart rhythm).

• Monitor for Adverse Effects: Be vigilant for signs and symptoms of side effects specific to the medication class and individual drug.

• Patient Education: Provide clear and comprehensive education on the medication’s purpose, dosage, timing, administration, potential side effects, drug/food interactions, importance of adherence, and when to contact the healthcare provider.

• Lifestyle Modifications: Reinforce the importance of lifestyle changes (diet, exercise, smoking cessation) as they are integral to managing cardiovascular conditions.

• Drug Interactions: Always check for potential interactions with other medications the patient is taking.

• Special Populations: Be aware of considerations for specific patient populations (e.g., older adults, patients with kidney or liver disease, pregnant women).