Table 1.

Pharmacological characteristics of spironolactone, canrenone, and eplerenone⁸⁶–⁹⁰

Characteristics	Spironolactone	Canrenone	Eplerenone
Molecular formula and mass, g/mol	C24H32O4S, 416.6	C22H28O3, 340.5	C24H30O6, 414.5
Mean peak plasma concentration, ng/mL	80a	181a	1720b
Time to peak plasma concentration, hours	2.6a	4.3a	1.5b
Elimination half-life, hours	1.3–2.0 (parent) 13.8–16.5 (metabolites)	18–22	4–6
Metabolism	Hepatic	Active metabolite	Hepatic (CYP3A4)
Excretion	Urine (primarily), feces	Urine, feces	Urine (67%), feces (32%)
Protein binding, %	90	98	50
Administration	Oral	Oral	Oral
Clinical indications	PA, edema (CHF, cirrhosis, or nephrotic syndrome), primary HTN, hypokalemia, and CHF (NYHA class II–IV)		LVEF ≤ 40% after AMI and primary HTN
Contraindications	Anuria, AKI, significant impairment of renal excretory function, or hyperkalemia		Plasma K+ > 5.5 mEq/L at initiation, CrCl ≤ 30 mL/min, use with strong CYP3A4 inhibitors, plasma Cr > 2.0 mg/dL in males and >1.8 mg/dL in females, use of K+ supplements or K+-sparing diuretics
Common adverse effects	Diarrhea, gynecomastia, sexual dysfunction, menstrual irregularities, hyperkalemia, metabolic acidosis, and hyperuricemia		Hyperkalemia, increased Cr, diarrhea, hyponatremia, vaginal bleeding, and hyperlipidemia
Manufacturer	Generic	Generic	Generic

Notes:

^aAfter administration of 100 mg of spironolactone daily for 15 days, on the 15th day, spironolactone was given immediately after a low-fat breakfast and blood was drawn thereafter;

^bafter oral administration of eplerenone at a dose of 100 mg as an aqueous solution.

Abbreviations: PA, primary hyperaldosteronism; CHF, congestive heart failure; NYHA, New York Heart Association; HTN, hypertension; AKI, acute kidney injury; LVEF, left ventricular ejection fraction; AMI, acute myocardial infarction; Cr, creatinine.