Hypertension (high blood pressure) is a leading risk factor for heart disease, stroke, and kidney failure. Medications that reduce blood pressure are called antihypertensives, and among the most important drug classes are ACE inhibitors and beta blockers.
These drugs lower blood pressure by targeting different pathways:
ACE inhibitors act on the Renin-Angiotensin-Aldosterone System (RAAS), preventing vasoconstriction.Both are widely used in hypertension, heart failure, and other cardiovascular conditions.
ACE Inhibitors (Angiotensin-Converting Enzyme Inhibitors)
Examples
CaptoprilEnalapril (Vasotec)
FosinoprilLisinopril (Prinivil)
(Suffix: “-pril”)
Mechanism of Action
Block conversion of angiotensin I → angiotensin II (a powerful vasoconstrictor).Result:
- Vasodilation (blood vessels widen).
- Lowered blood pressure.
- Reduced afterload in heart failure.
Clinical Uses
- Hypertension
- Heart failure
- Prevention of diabetic nephropathy
- Post-myocardial infarction (to prevent remodeling)
Side Effects (Mnemonic: ACE)
A – Angioedema: Swelling under the skin/mucosa, especially dangerous if affecting face/mouth.Other effects: Orthostatic hypotension, dizziness.
Nursing Considerations
- Monitor BP and pulse regularly.
- Watch for hypotension when changing positions (orthostatic hypotension).
- Monitor serum potassium (normal range: 3.5–5.0 mEq/L).
- Educate to avoid foods high in potassium and salt substitutes.
- Assess for angioedema – facial swelling requires immediate medical attention.
- Do not discontinue suddenly → risk of rebound hypertension.
- Contraindicated in pregnancy (teratogenic).
Beta Blockers
Examples
Atenolol(Suffix: “-lol”)
Mechanism of Action
- Block norepinephrine and epinephrine effects on the heart (sympathetic nervous system).
- Reduce heart rate, contractility, and cardiac output.
- Lower blood pressure and oxygen demand of the heart.
- Can be selective (beta-1) or non-selective (beta-1 and beta-2).
Clinical Uses
- Hypertension
- Stable angina (reduces chest pain frequency)
- Chronic/compensated heart failure (not acute failure)
- Dysrhythmias
- Post-MI protection
Side Effects (The “B’s of Beta Blockers”)
- Bradycardia (slow heart rate)
- Breathing problems (bronchospasm in non-selective types; dangerous in asthma/COPD)
- Bad for acute heart failure (can worsen contractility)
- Blood sugar masking (masks signs of hypoglycemia like tachycardia)
- Blood pressure lowered (hypotension)
Nursing Considerations
- Monitor for hypotension and bradycardia.
- Educate on slow position changes to avoid dizziness.
- Avoid non-selective beta blockers in asthma/COPD patients (risk of bronchospasm).
- Do not stop abruptly → risk of rebound hypertension and tachycardia.
- Monitor for signs of heart failure (edema, lung crackles, weight gain).
- Teach patients that beta blockers may mask hypoglycemia warning signs.
Comparison: ACE Inhibitors vs. Beta Blockers
| Feature | ACE Inhibitors | Beta Blockers |
|---|---|---|
| Suffix | “-pril” | “-lol” |
| Main Action | Block angiotensin II formation → vasodilation | Block sympathetic effects → ↓ HR, ↓ contractility |
| Uses | Hypertension, heart failure, diabetic kidney protection | Hypertension, angina, chronic HF, dysrhythmias |
| Side Effects | Angioedema, dry cough, hyperkalemia | Bradycardia, bronchospasm, fatigue, hypotension |
| Pregnancy Safety | Contraindicated | Generally avoided |
| Special Consideration | Avoid potassium supplements, monitor angioedema | Avoid in asthma/COPD with non-selective agents |
Conclusion
Both ACE inhibitors and beta blockers are cornerstone antihypertensive therapies, but they act through different mechanisms:
ACE inhibitors primarily cause vasodilation by inhibiting RAAS.Effective management requires close monitoring, patient education, and individualized therapy to prevent complications such as rebound hypertension, angioedema, or bradycardia.
FAQs on Antihypertensives
Q1: Why do ACE inhibitors cause a dry cough?
Because they increase bradykinin levels, which irritates the airways.
Q2: Can beta blockers be given to asthmatic patients?
Selective beta-1 blockers (like metoprolol) may be used cautiously, but non-selective ones (like propranolol) are contraindicated.
Q3: Why must these drugs not be stopped suddenly?
Stopping abruptly can cause rebound hypertension and worsen cardiovascular outcomes.
Q4: Which is better for diabetic patients – ACE inhibitors or beta blockers?
ACE inhibitors are often preferred as they protect the kidneys, while beta blockers may mask hypoglycemia.
Q5: Are these drugs safe during pregnancy?
ACE inhibitors are contraindicated; some beta blockers may be used under strict supervision.
