Eplerenone
INSPRA
Pronunciation: e-PLER-en-oen
“E pluribus unum Inspirer”
“INSPRA”ational background
Bananas in bunches → ↑ serum potassium
What it isSelective aldosterone receptor antagonist; heart failure and resistant hypertension.
Why this oneMortality benefit in HFrEF without the gynecomastia spironolactone causes, because it does not bind androgen receptors.
What limits itHyperkalemia is the limiting toxicity. CYP3A4-dependent, so strong inhibitors are contraindicated; weaker than spironolactone per milligram.
FDA-approved for
- hypertension (2002)
- heart failure (2003)
Off-label
- resistant hypertension
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Hypertension | adult | 50 mg QD | 50 mg BID if inadequate response | 50 mg BID (100 mg/day) |
Titration Allow ~4 weeks for full effect before increasing 50 mg QD to 50 mg BID.
Renal Contraindicated at CrCl <=30 mL/min (all patients); for hypertension also contraindicated at CrCl <50 mL/min or serum Cr >2.0 mg/dL (M) / >1.8 mg/dL (F).
Hepatic Undefined
With a concomitant moderate CYP3A inhibitor (hypertension): initiate 25 mg QD; for inadequate BP response may increase to max 25 mg BID.
Instructions
- Measure serum potassium before starting, within the first week, at one month, then periodically
- Check serum potassium and creatinine within 3–7 days of starting a moderate CYP3A inhibitor, ARB, or NSAID
Available strengths
- tab 25, 50 mg
Contraindications
- Serum potassium >5.5 mEq/L at initiation
- CrCl <=30 mL/min (all indications)
- Concomitant strong CYP3A inhibitors
- Hypertension: type 2 diabetes with microalbuminuria
- Hypertension: concomitant potassium supplements or potassium-sparing diuretics (amiloride, spironolactone, triamterene)
Cautions
- Hyperkalemia — higher risk with renal impairment, proteinuria, diabetes, or concomitant ARBs/NSAIDs/moderate CYP3A inhibitors; monitor serum potassium
Adverse reactions
- Hyperkalemia
- Headache, dizziness
- Gynecomastia / abnormal vaginal bleeding
- Increased GGT
Pregnancy Insufficient human data; animal studies show no adverse developmental effects at 31–32× human exposure.
Lactation Undefined
Cost
Generic entry2008
NO BOXED WARNINGS
Principal riskHyperkalemia
Classes and tags
Clinical profile
Legacy pregnancy categoryB
Defining liabilityHyperkalemia and kidney dysfunction, especially with RAAS blockers or CYP3A inhibitors.
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