Inspra (Eplerenone)

• Eplerenone (Inspra) acts as an aldosterone antagonist, addressing conditions linked to excess sodium retention and fluid overload.
• Hypertension: lowers blood pressure by promoting sodium excretion and reducing fluid volume.
• Heart failure: improves cardiac function and reduces hospitalizations by decreasing preload and afterload.
• Post‑myocardial infarction with left ventricular dysfunction: reduces risk of cardiovascular events in eligible patients.

• Eplerenone selectively binds to the mineralocorticoid (aldosterone) receptor in the distal nephron, competitively inhibiting aldosterone's action. This blockade diminishes sodium reabsorption and potassium excretion, leading to increased natriuresis and diuresis, which together lower blood pressure and decrease cardiac preload and afterload.

Eplerenone may cause a range of adverse reactions, which are grouped by frequency.

Common Side Effects

• Hyperkalemia
• Dizziness
• Headache
• Fatigue
• Nausea
• Diarrhea

Serious or Rare Side Effects

• Severe hyperkalemia
• Acute renal failure
• Angioedema
• Hepatic injury
• Severe hypotension
• Allergic reactions such as rash or urticaria

• When prescribing Eplerenone, clinicians should observe several precautionary measures to ensure patient safety.
• Monitor serum potassium: check potassium levels before initiation and periodically during therapy.
• Monitor renal function: assess creatinine and eGFR at baseline and follow‑up.
• Use caution in elderly: increased sensitivity to potassium changes.
• Avoid in patients with hyperkalemia: contraindicated when serum potassium >5.0 mmol/L.
• Contraindicated in pregnancy: category B, avoid use during pregnancy.
• Store at room temperature: keep in original packaging, protect from moisture.

Eplerenone interacts with several medicines; some combinations should be avoided while others require close monitoring.

Major Interactions (Avoid)

• Potassium supplements or potassium‑sparing diuretics: may cause dangerous hyperkalemia.
• ACE inhibitors or ARBs: increase risk of hyperkalemia and renal impairment.
• Cyclosporine: elevates eplerenone levels, raising toxicity risk.
• Trimethoprim‑sulfamethoxazole: can raise potassium levels.
• High‑dose NSAIDs: may impair renal function and potassium excretion.

Moderate Interactions (Monitor Closely)

• Thiazide diuretics: may affect electrolyte balance.
• Digoxin: monitor for signs of toxicity due to altered potassium.
• Lithium: monitor lithium levels as potassium changes affect clearance.
• Antifungal azoles (e.g., ketoconazole): may increase eplerenone concentrations.
• Beta‑blockers: observe for additive blood pressure lowering effect.