Antihypertensive Medications: Classes, Actions, and Nursing Safety

Antihypertensive medications are among the most commonly prescribed drugs in clinical practice. This note reviews the major classes, how they lower blood pressure, the side effects and life-threatening risks to watch for, and the nursing assessments that keep patients safe.

Major Antihypertensive Classes

• ACE inhibitors (e.g., lisinopril) — lower BP and provide kidney protection.
• ARBs (e.g., losartan) — lower BP without causing the ACE-inhibitor cough.
• Beta blockers (e.g., metoprolol) — lower heart rate and BP.
• Calcium channel blockers (CCBs) (e.g., amlodipine) — lower BP or slow HR.
• Diuretics (e.g., furosemide) — decrease fluid volume.
• Vasodilators (e.g., hydralazine) — decrease afterload.

First-Line Hypertension Medications

1. Thiazide diuretics
2. ACE inhibitors
3. ARBs
4. Calcium channel blockers

Mechanisms of Action

• ACE inhibitors — block formation of angiotensin II.
• ARBs — block angiotensin II at the receptor.
• Beta blockers — decrease heart rate.
• CCBs — cause vasodilation or slow heart rate.
• Diuretics — remove excess fluid.

Common Side Effects

• ACE inhibitors — dry cough, hyperkalemia.
• ARBs — hyperkalemia.
• Beta blockers — bradycardia, fatigue.
• CCBs — constipation, peripheral edema.
• Diuretics — electrolyte imbalances.

Life-Threatening Risks

• Severe hypotension
• Bradycardia
• Electrolyte disturbances
• Angioedema (with ACE inhibitors and ARBs)

Hold Parameters

• SBP < 90–100 mmHg — hold medication.
• HR < 60 bpm — hold medication.
• Critical electrolyte imbalance — hold and notify the provider.

Nursing Safety Rules

• Check blood pressure before administration.
• Monitor electrolytes and renal labs.
• Teach patients to change positions slowly to prevent orthostatic hypotension.
• Promote medication adherence.
• Do not stop beta blockers abruptly — risk of rebound hypertension and tachycardia.

Common Exam Traps

• Confusing antihypertensive drug classes and their actions.
• Giving medications despite hypotension.
• Ignoring potassium levels, especially with ACE inhibitors and ARBs.
• Abrupt discontinuation of beta blockers.
• Forgetting pregnancy contraindications (ACE inhibitors and ARBs).

Key Takeaways

• First-line therapy includes thiazides, ACE inhibitors, ARBs, and CCBs.
• ACE inhibitors and ARBs lower BP and protect the kidneys but can cause hyperkalemia and angioedema.
• Beta blockers lower HR — never stop abruptly.
• Always assess BP and HR before giving any antihypertensive; hold if SBP < 90–100 or HR < 60.
• Monitor electrolytes and renal function routinely.
• ACE inhibitors and ARBs are contraindicated in pregnancy.