Eplerenone (Inspra) is a selective aldosterone receptor antagonist, primarily indicated for the treatment of adult patients with heart failure following myocardial infarction, as well as adult hypertension. As an effective prescription drug, while it delivers therapeutic benefits, it may also be accompanied by certain adverse reactions and risks.

Adverse Reactions of Eplerenone (Inspra)

Common Adverse Reactions in Patients with Heart Failure After Myocardial Infarction

Hyperkalemia: This is one of the most concerning adverse reactions of eplerenone. In pivotal clinical trials, the incidence of hyperkalemia was significantly higher in patients treated with eplerenone.

Abnormal elevation of serum potassium levels may trigger serious cardiac events such as arrhythmias.

Adverse Reactions in Hypertension Treatment

In hypertensive patients, eplerenone is generally well-tolerated, with a low incidence of adverse reactions.

The rate of treatment discontinuation due to adverse reactions is similar to that in patients not receiving active treatment.

Reported adverse reactions include headache, dizziness, etc. There have been reports of gynecomastia in male patients and abnormal vaginal bleeding in female patients, with the incidence potentially increasing with prolonged treatment duration.

Severe Adverse Reactions

Severe hyperkalemia: This is the most serious risk, which may lead to muscle weakness, bradycardia or irregular heartbeat, and even cardiac arrest.

Angioedema: Manifested as swelling of the face, lips, tongue or throat, which may affect breathing and is classified as a severe allergic reaction.

Skin rash.

Precautions for Eplerenone (Inspra)

Strictly Follow Contraindications

For all patients: Serum potassium level > 5.5 mEq/L at the initiation of treatment; creatinine clearance ≤ 30 mL/min; concomitant use with potent CYP3A inhibitors (e.g., ketoconazole, clarithromycin, ritonavir, etc.).

Additional contraindications for hypertensive patients: Type 2 diabetes mellitus complicated with microalbuminuria; serum creatinine level > 2.0 mg/dL in males or > 1.8 mg/dL in females; creatinine clearance < 50 mL/min; concomitant use with potassium supplements or potassium-sparing diuretics (e.g., amiloride, spironolactone).

Prevent Hyperkalemia

Hyperkalemia is the core risk of eplerenone treatment. The risk is higher in patients with renal insufficiency, diabetes mellitus, proteinuria, as well as those concomitantly using angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, non-steroidal anti-inflammatory drugs or moderate CYP3A inhibitors.

Monitoring requirements: Serum potassium level must be measured before the start of treatment, and re-examined regularly within the first week of treatment, one month later and after dose adjustment.

Important Management of Drug Interactions

Avoid concomitant use: Concurrent administration with potent CYP3A inhibitors is prohibited.

Dose adjustment: When co-administered with moderate CYP3A inhibitors (e.g., verapamil, erythromycin, fluconazole), the dose of eplerenone must be reduced. For patients with heart failure after myocardial infarction, the daily dose should not exceed 25 mg. For hypertensive patients, treatment should be initiated at a daily dose of 25 mg.

Cautious concomitant use: Co-administration with angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers, non-steroidal anti-inflammatory drugs or lithium salts will increase the risk of hyperkalemia, blood pressure fluctuations or lithium toxicity. Close monitoring of serum potassium levels, renal function or serum lithium concentrations is mandatory.