Overview
This lecture covers the ABCs of antihypertensive drugs: ACE inhibitors, Beta Blockers, and Calcium Channel Blockers, including mechanisms, side effects, and key nursing considerations.
ACE Inhibitors
- ACE = Angiotensin Converting Enzyme; blocks conversion of angiotensin I to II, resulting in vasodilation and lower blood pressure.
- Blocks aldosterone, reducing sodium and water retention, and decreases peripheral vascular resistance.
- Does not increase cardiac output, heart rate, or contractility.
- Common side effects: dry cough, increased potassium (hyperkalemia), rash, taste changes, headache, low blood pressure (orthostatic hypotension), proteinuria.
- Serious adverse effects: angioedema, neutropenia, severe hypotension.
- Monitor potassium and white blood cell count (risk of neutropenia).
- Names typically end in "-pril" (e.g., captopril).
- Nursing interventions: monitor BP, labs, rise patient slowly, administer on empty stomach, avoid potassium-rich salt substitutes, use caution with lithium and NSAIDs.
Beta Blockers
- Block sympathetic stimulation and epinephrine effects on the heart, lowering heart rate, contractility, and AV conduction.
- Beta-1 (heart) and Beta-2 (lungs); blocking Beta-2 may cause bronchoconstriction.
- Common side effects: bradycardia, lethargy, weakness, dizziness.
- Serious adverse effects: heart failure, bronchoconstriction (contraindicated in COPD/asthma), hypoglycemia in diabetics (certain beta blockers).
- Names typically end in "-lol" (e.g., atenolol, propranolol).
- Nursing interventions: monitor BP and heart rate, hold if too low, assess for weakness/fainting, teach patient not to stop suddenly (risk of rebound hypertension).
Calcium Channel Blockers
- Block calcium influx in heart/arteries, decreasing contractility, heart rate, and peripheral resistance.
- Relax blood vessels, lower BP, and reduce heart's oxygen demand.
- Often first-line therapy for newly diagnosed hypertension, especially in elderly and people of color.
- Common side effects: edema (especially lower extremities), nausea, constipation, headache, dizziness.
- Serious adverse effects: arrhythmias, bradycardia.
- Names often end in "-pine" (e.g., nifedipine), but not always.
- Nursing interventions: give before meals, monitor BP and weight (fluid overload), avoid grapefruit juice.
Key Terms & Definitions
- ACE inhibitor — Drug blocking angiotensin I to II conversion, lowering BP.
- Beta blocker — Drug blocking beta receptors, reducing heart workload.
- Calcium channel blocker — Drug blocking calcium entry in heart/arteries, causing vasodilation.
- Orthostatic hypotension — Sudden BP drop when standing up.
- Hyperkalemia — Elevated potassium level in blood.
- Angioedema — Swelling under the skin, potentially dangerous.
Action Items / Next Steps
- Review nursing responsibilities for each drug class.
- Memorize common drug endings: "-pril" (ACE), "-lol" (beta blockers), "-pine" (CCBs, often).
- Monitor patient labs and vital signs according to drug class.
- Avoid grapefruit juice with calcium channel blockers.