Angiotensin Receptor Blockers (ARBs) inhibit the effects of Angiotensin II by selectively blocking the AT1 receptor.

They reduce systemic vascular resistance, aldosterone secretion, and pathologic cardiac remodeling.

ARBs are commonly used in: • Hypertension • Heart failure (HFrEF) • Chronic kidney disease • Post-myocardial infarction • Diabetic nephropathy

• Block Angiotensin II Type 1 (AT1) receptors • Prevent vasoconstriction • Decrease aldosterone release • Reduce sympathetic activation

Effects:

• ↓ Systemic vascular resistance (afterload) • ↓ Sodium retention • ↓ Cardiac remodeling • ↓ Blood pressure

Unlike ACE Inhibitors, ARBs do NOT increase bradykinin.

ACE inhibitors increase bradykinin levels. ARBs do not.

Result: • Much lower incidence of dry cough • Lower risk of angioedema (but not zero)

• First-line therapy • Alternative when ACE inhibitors are not tolerated

→ Hypertension Module

• Used when ACE inhibitors not tolerated • Reduce mortality and hospitalizations

→ Heart Failure Module

• Reduce intraglomerular pressure • Reduce proteinuria • Slow CKD progression

• Used if ACE inhibitor intolerance • Prevent ventricular remodeling

• Losartan • Valsartan • Candesartan • Irbesartan • Olmesartan • Telmisartan • Azilsartan

All ARBs share similar mechanism and outcome benefits.

Differences are largely pharmacokinetic.

• Hyperkalemia • Hypotension • Mild creatinine elevation • Rare angioedema

Compared to ACE inhibitors: • Less cough • Lower angioedema risk

Monitor:

• Serum creatinine • Potassium

Check labs 1–2 weeks after initiation or dose change.

A creatinine rise <30% is generally acceptable.

• Pregnancy • Bilateral renal artery stenosis • Concomitant ACE inhibitor use • Severe hyperkalemia

ACE Inhibitors: • Block Angiotensin II production • Increase bradykinin • More cough

ARBs: • Block AT1 receptor • No bradykinin increase • Better tolerated

Both: • Reduce mortality in HFrEF • Protect kidneys in diabetes • First-line for hypertension

✔ Equivalent BP reduction compared to ACE inhibitors ✔ Preferred if ACE inhibitor causes cough ✔ Monitor potassium carefully ✔ Do NOT combine with ACE inhibitors ✔ Core therapy in CKD and HFrEF

Related:

→ ACE Inhibitors → Hypertension Module → Heart Failure Module → Return to CV Modules