Eplerenone (Inspra) is an aldosterone antagonist primarily indicated for the treatment of heart failure following acute myocardial infarction and hypertension in adults.
Dosage and Administration, Recommended Dose of Eplerenone (Inspra)
Treatment of Heart Failure after Myocardial Infarction
(1) The initial therapeutic dose is 25 mg once daily. In patients who tolerate the drug, titration to the recommended dose of 50 mg once daily is preferred within 4 weeks.
(2) After the start of treatment, the dose needs to be adjusted based on serum potassium levels.
(3) When the serum potassium level is below 5.0 mEq/L, the dose can be adjusted to 25 mg every other day to 25 mg once daily, or increased from 25 mg once daily to 50 mg once daily.
(4) No dose adjustment is required when serum potassium is between 5.0–5.4 mEq/L.
(5) When serum potassium is between 5.5–5.9 mEq/L, the dose should be reduced from 50 mg once daily to 25 mg once daily, or from 25 mg once daily to 25 mg every other day, or even temporarily discontinued.
(6) When serum potassium ≥ 6.0 mEq/L, administration should be suspended, and treatment should be restarted at 25 mg every other day once the potassium level drops to < 5.5 mEq/L.
Treatment of Hypertension
(1) The recommended starting dose is 50 mg once daily.
(2) Eplerenone can be used alone or in combination with other antihypertensive drugs.
(3) For patients with an inadequate blood pressure response, the dose can be increased to 50 mg twice daily.
(4) Higher doses are not recommended, as they do not produce greater antihypertensive effects than 100 mg (total daily dose) but will increase the risk of hyperkalemia.
Dose Adjustment of Eplerenone (Inspra)
Serum Potassium Monitoring
(1) Serum potassium levels must be measured before initiating eplerenone treatment, within the first week, and one month after treatment initiation or dose adjustment, followed by regular assessments thereafter.
(2) When patients start using moderate CYP3A inhibitors, ACE inhibitors, angiotensin II receptor blockers, or non-steroidal anti-inflammatory drugs (NSAIDs), serum potassium and serum creatinine should be checked within 3–7 days.
Concomitant Medication Adjustment
(1) When used in combination with moderate CYP3A inhibitors (such as erythromycin, saquinavir, verapamil, and fluconazole), patients with heart failure after myocardial infarction should not exceed a dose of 25 mg once daily.
(2) For hypertensive patients using moderate CYP3A inhibitors, treatment should start at 25 mg once daily; if the blood pressure response is inadequate, the dose can be increased to a maximum of 25 mg twice daily.
Medication Use in Special Populations
Renal Impairment
(1) Eplerenone is contraindicated in patients with creatinine clearance ≤ 30 mL/min.
(2) In the treatment of hypertension, it is also contraindicated in patients with creatinine clearance < 50 mL/min, serum creatinine > 2.0 mg/dL in males, or > 1.8 mg/dL in females.
(3) In patients with severe renal impairment, steady-state AUC and Cmax are increased by 38% and 24%, respectively.
Pregnancy
(1) Available data on the use of eplerenone during pregnancy are insufficient to determine the risk of drug-related major birth defects, miscarriage, or adverse maternal or fetal outcomes.
(2) Hypertension during pregnancy increases maternal risks of preeclampsia, gestational diabetes, preterm birth, and delivery complications.
Lactation
(1) There are no data on whether eplerenone is present in human milk, nor on its effects on breastfed infants or milk production.
(2) However, eplerenone is present in the milk of lactating rats; when a drug is present in animal milk, it is likely to be present in human milk as well.
