Inspra (Eplerenone)

Eplerenone is a mineralocorticoid receptor antagonist used in cardiovascular disease management.

• Hypertension: lowers blood pressure by reducing sodium and water retention.
• Heart failure with reduced ejection fraction: improves survival and reduces hospitalizations by decreasing cardiac remodeling.
• Post‑myocardial infarction: helps prevent heart failure progression and reduces risk of cardiovascular events.

• Eplerenone selectively blocks the binding of aldosterone to mineralocorticoid receptors in the distal nephron and cardiovascular tissues. By antagonizing this receptor, it inhibits sodium reabsorption and potassium excretion, leading to natriuresis and diuresis, and attenuates aldosterone‑mediated myocardial fibrosis and vascular remodeling. The resulting electrolyte balance reduces fluid overload, while the anti‑fibrotic effect contributes to improved cardiac function over time in patients.

Eplerenone may cause a range of adverse reactions, varying in frequency and severity.

Common Side Effects

• Hyperkalemia: elevated blood potassium levels.
• Dizziness: light‑headed sensation, especially on standing.
• Headache: mild to moderate intensity.
• Fatigue: feeling of tiredness or reduced energy.
• Diarrhea: loose stools.
• Cough: non‑productive respiratory irritation.

Serious or Rare Side Effects

• Severe hyperkalemia: potentially life‑threatening potassium excess.
• Acute kidney injury: sudden decline in renal function.
• Gynecomastia: breast tissue enlargement in males.
• Hepatic dysfunction: abnormal liver enzyme elevations.
• Allergic reactions: rash, itching, or anaphylaxis.

When prescribing eplerenone, clinicians should consider several safety precautions to minimize risk.

• Renal function: assess baseline kidney function and monitor regularly.
• Serum potassium: check potassium levels before initiation and during therapy.
• Concomitant drugs: avoid use with potassium‑sparing diuretics or ACE inhibitors without monitoring.
• Pregnancy: contraindicated; avoid use in pregnant women.
• Breastfeeding: not recommended due to potential infant exposure.
• Store at ambient temperature: keep below 25 °C in the original packaging, protect from moisture and light.

Eplerenone can interact with other medicines, altering its efficacy or safety profile.

Major Interactions (Avoid)

• Potassium‑sparing diuretics (e.g., spironolactone, amiloride): may cause dangerous hyperkalemia.
• ACE inhibitors or ARBs: combined use increases risk of hyperkalemia and renal impairment.
• NSAIDs: can reduce renal clearance and exacerbate potassium retention.

Moderate Interactions (Monitor Closely)

• Digoxin: increased serum levels may occur.
• Antifungal agents (e.g., ketoconazole): may raise eplerenone concentrations.
• Beta‑blockers: may enhance antihypertensive effect, requiring blood pressure monitoring.