RAAS Drugs: ACEi vs ARBs vs Direct Renin Inhibitor
A client on lisinopril develops a persistent dry cough — do you hold the drug, switch classes, or reassure? Picking the wrong answer means you don't know which side effect belongs to which drug class. The NCLEX exploits this confusion repeatedly across pharmacology and safety questions.
Comparison
- Block ACE → ↓ angiotensin II, ↑ bradykinin
- Block AT1 receptor → ↓ angiotensin II effect
- Inhibit renin directly → ↓ angiotensin I
- Hypertension
- Heart failure; diabetic nephropathy
- Hypertension
- Heart failure; diabetic nephropathy
- Hypertension
- PO; –pril (lisinopril, enalapril)
- PO; –sartan (losartan, valsartan)
- PO; aliskiren
- Blood pressure
- ★Dry cough (bradykinin)
- Blood pressure
- ★No cough — alternative when ACEi cough
- Blood pressure
- Diarrhea (high doses)
- Monitor potassium & renal function
- Monitor potassium & renal function
- Monitor potassium & renal function
- Hyperkalemia — avoid K⁺ supplements/salt substitutes
- Dry cough + angioedema (bradykinin)
- Hyperkalemia — avoid K⁺ supplements/salt substitutes
- Angioedema rare
- Hyperkalemia — avoid K⁺ supplements/salt substitutes
- Diarrhea; angioedema
- Pregnancy — fetal toxicity (black box)
- Angioedema — airway emergency, stop drug
- Pregnancy — fetal toxicity (black box)
- Angioedema — airway emergency, stop drug
- Pregnancy — fetal toxicity (black box)
- Angioedema — airway emergency, stop drug
- Avoid with K-sparing diuretics
- Avoid with K-sparing diuretics
- Avoid with K-sparing diuretics
- Rise slowly (first-dose hypotension)
- Rise slowly (first-dose hypotension)
- Rise slowly (first-dose hypotension)
ACE Inhibitors
- Block ACE → ↓ angiotensin II, ↑ bradykinin
ARBs
- Block AT1 receptor → ↓ angiotensin II effect
ACE Inhibitors
- Hypertension
- Heart failure; diabetic nephropathy
ARBs
- Hypertension
- Heart failure; diabetic nephropathy
ACE Inhibitors
- PO; –pril (lisinopril, enalapril)
ARBs
- PO; –sartan (losartan, valsartan)
ACE Inhibitors
- Blood pressure
- ★Dry cough (bradykinin)
ARBs
- Blood pressure
- ★No cough — alternative when ACEi cough
ACE Inhibitors
- Monitor potassium & renal function
ARBs
- Monitor potassium & renal function
ACE Inhibitors
- Hyperkalemia — avoid K⁺ supplements/salt substitutes
- Dry cough + angioedema (bradykinin)
ARBs
- Hyperkalemia — avoid K⁺ supplements/salt substitutes
- Angioedema rare
ACE Inhibitors
- Pregnancy — fetal toxicity (black box)
- Angioedema — airway emergency, stop drug
ARBs
- Pregnancy — fetal toxicity (black box)
- Angioedema — airway emergency, stop drug
ACE Inhibitors
- Avoid with K-sparing diuretics
ARBs
- Avoid with K-sparing diuretics
ACE Inhibitors
- Rise slowly (first-dose hypotension)
ARBs
- Rise slowly (first-dose hypotension)
★ marks the fact that sets a column apart.
Clinical Pearl
Cough → ACEi; switch to ARB (no cough, no bradykinin). Aliskiren (DRI) blocks renin at the top of the cascade — never combine it with an ACEi or ARB in diabetes (ALTITUDE). Suffix tells the class: -pril, -sartan, aliskiren.
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