Heart failure survival hinges on four drug classes working together — remove one pillar and mortality climbs. Knowing which drugs do what, and when to hold them, is NCLEX gold.
Guideline-directed medical therapy (GDMT) for HFrEF (EF ≤40%) rests on four pillars: ACE inhibitors or ARBs (or sacubitril/valsartan), beta-blockers (carvedilol, metoprolol succinate, bisoprolol), aldosterone antagonists (spironolactone, eplerenone), and SGLT2 inhibitors (dapagliflozin, empagliflozin). ACE inhibitors reduce afterload and block harmful neurohormonal remodeling — monitor for dry cough, hyperkalemia, and angioedema. ARBs substitute when cough is intolerable but never combine with an ACE inhibitor. Sacubitril/valsartan (ARNI) replaces the ACE/ARB and requires a 36-hour washout from any ACE inhibitor to prevent angioedema. Beta-blockers are started at low doses when the patient is euvolemic — never during acute decompensation — and titrated slowly. They reduce mortality by blunting sympathetic overdrive. Spironolactone is potassium-sparing; potassium and creatinine must be monitored closely, especially when combined with ACE inhibitors. Loop diuretics (furosemide) manage volume overload but are symptom relief only — they do not improve survival. Digoxin may be added to reduce hospitalizations but does not reduce mortality.
Key Distinctions
Don't confuse survival drugs (ACE inhibitors, beta-blockers, aldosterone antagonists, SGLT2 inhibitors) with symptom-relief drugs (loop diuretics, digoxin) — the NCLEX tests whether a medication improves mortality or just manages symptoms. Students mix up spironolactone (potassium-sparing, watch for hyperkalemia) with furosemide (potassium-wasting, watch for hypokalemia). Beta-blockers are contraindicated in acute decompensation but are essential in stable chronic HF — the timing of initiation is a classic test trap.
Clinical Pearl
Furosemide makes the patient feel better; ACE inhibitors, beta-blockers, spironolactone, and SGLT2 inhibitors make the patient live longer. The NCLEX loves this distinction.