Inspra (Eplerenone)

Eplerenone is used in cardiovascular conditions that involve aldosterone‑mediated fluid retention.

• Hypertension: lowers blood pressure by decreasing sodium reabsorption and water retention.
• Heart failure (post‑myocardial infarction): improves survival and reduces hospitalizations by limiting adverse cardiac remodeling.
• Heart failure with reduced ejection fraction: decreases morbidity and mortality in patients with systolic dysfunction.

• Eplerenone selectively blocks the mineralocorticoid receptor in the distal nephron, competing with aldosterone for binding. This antagonism prevents aldosterone‑induced transcription of sodium channels and pumps, reducing sodium and water reabsorption while conserving potassium. The resulting natriuretic and potassium‑sparing effect lowers intravascular volume and blood pressure, and attenuates cardiac remodeling in heart‑failure states.

Eplerenone may cause a range of adverse reactions, which are classified by frequency and severity.

Common Side Effects

• Hyperkalemia: elevated blood potassium levels.
• Dizziness: sensation of light‑headedness.
• Headache: mild to moderate cranial pain.
• Fatigue: generalized tiredness.
• Nausea: upset stomach.
• Abdominal pain: discomfort in the stomach area.

Serious or Rare Side Effects

• Severe hyperkalemia: potentially life‑threatening potassium excess.
• Renal impairment: decline in kidney function.
• Angioedema: swelling of face, lips, or airway.
• Hepatic dysfunction: abnormal liver enzyme elevations.
• Menstrual irregularities: changes in cycle patterns.
• Anaphylactic reaction: rare severe allergic response.

When prescribing eplerenone, clinicians should observe several precautionary measures to ensure patient safety.

• Monitor serum potassium: check levels before initiation and periodically during therapy.
• Assess renal function: evaluate creatinine clearance prior to start and during treatment.
• Use caution in diabetes: patients may have altered potassium handling.
• Avoid in pregnancy: category D indicates potential fetal risk; discontinue if pregnancy occurs.
• Adjust dose in elderly: start with lower dose and titrate cautiously.
• Store at ambient temperature: keep tablets in original packaging, protect from moisture and direct sunlight.

Eplerenone interacts with several medicines; awareness of the interaction level guides clinical decisions.

Major Interactions (Avoid)

• ACE inhibitors or ARBs: combined use can cause dangerous hyperkalemia.
• Potassium‑sparing diuretics or supplements: increase risk of severe hyperkalemia.
• Cyclosporine: may raise eplerenone plasma concentrations.

Moderate Interactions (Monitor Closely)

• NSAIDs: can impair renal function and elevate potassium.
• Digoxin: altered renal clearance may require dose adjustment.
• Lithium: concurrent use may increase lithium levels and toxicity.