spironolactone (Rx)

Brand and Other Names:Aldactone, CaroSpir
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Dosing & Uses


Dosage Forms & Strengths


  • 25mg
  • 50mg
  • 100mg

Oral suspension (CaroSpir)

  • 5mg/mL

Primary Hyperaldosteronism

Tablet only

Short-term preoperative treatment of patients with primary hyperaldosteronism

Long-term maintenance therapy for patients with discrete aldosterone-producing adrenal adenomas who are not candidates for surgery or for patients with bilateral micro or macronodular adrenal hyperplasia (idiopathic hyperaldosteronism)

100-400 mg PO qDay in preparation for surgery initially

May be used as long-term maintenance therapy at the lowest effective for patients who are considered unsuitable for surgery

Edematous Conditions

Management of edema in patients with cirrhosis of the liver when edema are unresponsive to fluid and sodium restriction or nephrotic syndrome when treatment of the underlying disease, fluid restriction and sodium intake, and the use of other diuretics produce an inadequate response


  • 100 mg qDay or divided q12hr for 5 days initially; then adjust does based on patient response; range: 25-200 mg PO qDay or divided q12hr

PO suspension

  • 75 mg PO qDay or divided doses initially; if sole therapy, administer for ≥5 days before increasing dose to obtain effect

Essential Hypertension

Adjunctive therapy for hypertension, to lower blood pressure


  • 25-100mg PO qDay or divided q12hr initially; may adjust dosage to patient response q2weeks

PO suspension

  • 20-75 mg PO qDay or divided doses initially; may adjust dosage to patient response q2weeks
  • See Dosing Considerations

Congestive Heart Failure

Indicated for treatment of NYHA Class III-IV heart failure and reduced ejection fraction (EF) to increase survival, manage edema, and reduce the need for hospitalization for heart failure

ACC/AHA guidelines recommend aldosterone antagonist to be added to an ACE inhibitor or ARB, plus a beta-blocker; patient conditions may also require additional medications (eg, loop diuretics, hydralazine, nitrates, digoxin)


  • 25mg/day PO initially if serum potassium ≤5 mEq/L and eGFR >50 mL/min/1.73 m²; if tolerated, may increase to 50 mg/day as clinically indicated; if 25 mg/day not tolerated, reduce frequency to qoD

PO suspension

  • 20 mg PO qDay; if initial 20 mg dose is tolerated, dosage can be increased to 37.5 mg as clinically indicated


Range: 25-100 mg PO qDay

Hirsutism (Off-label)

Women with hirsutism

50-200 mg PO qDay or divided q12hr

Acne (Off-label)

Females with hormonal acne

50-200 mg PO qDay or divided q12hr

Dosing Modifications

Renal impairment

  • Patients with renal impairment are at increased risk of hyperkalemia; monitor potassium closely
  • PO suspension for treatment of patients who develop hyperkalemia on 20 mg PO qDay may reduce dose to 20 mg PO qOD
  • Patients who develop hyperkalemia on 25 mg PO qDay may reduce to 25 mg PO qOD
  • CrCl >50 mL/min/1.73 m²: 20 mg qDay (oral suspension); 25 mg qDay (tablets)
  • CrCl 30-50 mL/min/1.73 m²: Consider initiating at 10 mg qDay (oral suspension) and 25 mg qOD (tablets)

Overdose Management

May use normal saline for volume replacement

May use dopamine or norepinephrine to treat hypotension

Treat hyperkalemia with IV glucose (dextrose 25% in water), concurrently with rapid-acting insulin and IV sodium bicarbonate; oral/rectal solutions of Kayexalate in sorbitol can be used if needed

If dysrhythmia due to decreased K+ or Mg+ suspected, replace aggressively

Discontinue treatment if no symptoms after 6 hr

Dosing Considerations

Oral formulation

  • PO suspension formulation is not therapeutically equivalent to tablet
  • If PO suspension requires a dose titration >100 mg, use tablet
  • For hypertension: Doses >75 mg/day may not provide additional reductions in blood pressure

Dosage Forms & Strengths


  • 25mg
  • 50mg
  • 100mg

Edema (Off-label)

CHF, cirrhosis, ascites, and nephrotic syndrome

1-3.3 mg/kg/day PO or divided q12hr; not to exceed 3.3 mg/kg/day or up to 100 mg/day  

Hypertension (Off-label)

Among therapeutic options recommended by the National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents

1-3.3 mg/kg/day PO or divided q12hr; not to exceed 3.3 mg/kg/day or 100 mg/day  

Hyperaldosteronism (Orphan)

Orphan designation for primary hyperaldosteronism


  • CMP Pharma, Inc; PO Box 147, 8026 US Highway 264A; Farmville, NC 27828

Substantially excreted by the kidney, and risk of adverse reactions to this drug may be greater in patients with impaired renal function; monitor renal function



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            Adverse Effects

            Frequency Not Defined

            Gastric bleeding



            Decreased libido

            Inability to achieve or maintain erection

            Postmenopausal bleeding

            Breast and nipple pain




            Maculopapular or erythematous cutaneous eruptions

            Anaphylactic reactions



            Electrolyte disturbances




            Mental confusion





            Renal dysfunction (including renal failure)





            Mental confusion



            Stevens-Johnson syndrome

            Toxic epidermal necrolysis

            Drug rash with eosinophilia and systemic symptoms (DRESS)



            Menstrual disorders

            Abdominal cramping





            Breast pain


            Electrolyte disturbances

            Leg cramps






            Black Box Warnings

            Spironolactone has been shown to be a tumorigen in chronic toxicity studies in rats; use only for specified indications



            Addison disease or other conditions associated with hyperkalemia

            Coadministration with eplerenone


            Gynecomastia reported and usually reversible

            Hyponatremia, hypomagnesemia, hypocalcemia, hypochloremic alkalosis, and hyperglycemia may occur

            Asymptomatic hyperuricemia can occur and rarely gout may occur; monitor serum electrolytes, uric acid, and blood glucose periodically In cirrhosis, avoid electrolyte and acid/base imbalances that might lead to hepatic encephalopathy

            Hyperkalemia may occur; monitor serum potassium within 1 week of initiation or titration of spironolactone and regularly thereafter; if hyperkalemia occurs, reduce dose or discontinue treatment and treat hyperkalemia

            Excessive diuresis may cause symptomatic dehydration, hypotension and worsening renal function, particularly in salt-depleted patients or those taking angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs)

            Drug interactions overview

            • Coadministration of PO suspension and lithium reduces the renal clearance of lithium, inducing a high risk of lithium toxicity
            • Reported that of coadministration of PO suspension and an NSAID can reduce the diuretic, natriuretic, and antihypertensive effect of loop, potassium-sparing, and thiazide diuretics
            • NSAID administration can reduce diuretic, natriuretic, and antihypertensive effect of diuretics; when spironolactone and NSAIDs are used concomitantly, monitor closely to determine if the desired effect of the diuretic is obtained
            • Acetylsalicylic acid may reduce the efficacy of spironolactone; coadministration with acetylsalicylic acid may need to be titrated to higher maintenance dose and monitor closely to determine if the desired effect is obtained
            • Coadministration of spironolactone with potassium supplementation, salt substitutes containing potassium, a diet rich in potassium, or drugs that can increase potassium (eg, ACE inhibitors, ARBs, NSAIDs, heparin and low molecular weight heparin) may lead to severe hyperkalemia
            • Risk of worsening of renal function can also occur with concomitant use of nephrotoxic drugs (eg, aminoglycosides, cisplatin, NSAIDs); monitor volume status and renal function periodically
            • Spironolactone and its metabolites interfere with radioimmunoassays for digoxin and increase the apparent exposure to digoxin; use an assay that does not interact with spironolactone
            • Hyperkalemic metabolic acidosis reported in patients given spironolactone concurrently with cholestyramine

            Pregnancy & Lactation


            Based on mechanism of action and findings in animal studies, spironolactone may affect sex differentiation of the male during embryogenesis; rat embryofetal studies report feminization of male fetuses and endocrine dysfunction in females exposed to spironolactone in utero

            Limited available data did not demonstrate an association of major malformations or other adverse pregnancy outcomes with spironolactone; risks may occur to the mother and fetus associated with heart failure, cirrhosis, and poorly controlled hypertension during pregnancy

            Potential risk to the male fetus due to antiandrogenic properties of spironolactone; avoid spironolactone in pregnant women or advise a pregnant woman of the potential risk to a male fetus

            Disease-associated maternal and embryo/fetal risks

            • Pregnant women with CHF are at increased risk for preterm birth; stroke volume and heart rate increase during pregnancy, increasing cardiac output, especially during the first trimester; closely monitor pregnant patients with CHF
            • Pregnant women with symptomatic cirrhosis generally have poor outcomes (eg, hepatic failure, variceal hemorrhage, preterm delivery, fetal growth restriction, and maternal death); pregnant women with cirrhosis of the liver should be monitored and managed accordingly
            • Hypertension in pregnancy increases the maternal risk for preeclampsia, gestational diabetes, premature delivery, and delivery complications (eg, need for cesarean delivery, postpartum hemorrhage); hypertension increases the fetal risk for intrauterine growth restriction and death


            Not present in breastmilk; however, limited data from a lactating woman at 17 days postpartum reports the presence of the active metabolite, canrenone, in human breast milk in low amounts that are expected to be clinically inconsequential; in this case, there were no adverse effects reported for the breastfed infant after short term exposure to spironolactone; however, long term effects on a breastfed infant are unknown; there are no data on spironolactone effects on milk production

            Consider the developmental and health benefits of breastfeeding along with the mother’s clinical need for the drug, and any potential adverse effects on the breastfed infant from the drug or from the underlying maternal condition

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.



            Mechanism of Action

            Aldosterone antagonist with diuretic and antihypertensive effects; competitive binding of receptors at aldosterone-dependent Na-K exchange site in distal tubules results in increased excretion of Na+, Cl-, and water and retention of K+ and H+

            Increases testosterone clearance and estradiol production; blocks conversion of potent androgens to weaker ones in peripheral tissues


            Bioavailability: 73% (tablet)

            Onset: 2-4 hr (tablet)

            Duration: 2-3 days (tablet)

            Peak serum time: 2.6-4.3 hr (tablet); 0.5-1.5 hr (PO suspension); 2.5-5 hr (PO suspension, active metabolite)

            A high fat and high calorie meal (57% of the ~1000 kcal of the meal were from fat) increased the bioavailability of spironolactone (as measured by AUC) by ~90%


            Protein bound: 90%


            Metabolized by the liver and kidneys

            Metabolites: Canrenone, 7-alpha-thiomethylspirolactone, 6-beta-hydroxy-7-alpha-thiomethylspirolactone (active)


            Half-life (tablet): 1.3-1.4 hr (parent drug); 16.5 hr (canrenone); 13.8 hr (7-α-[thiomethyl] spirolactone [TMS]); 15 hr (6-ß-hydroxy-7-α-[thiomethyl] spirolactone [HTMS])

            Half-life (PO suspension): 1-2 hr (parent drug); 10-35 hr (canrenone, 7-α-[thiomethyl] spirolactone [TMS], 6-ß-hydroxy-7-α-[thiomethyl] spirolactone [HTMS])

            Excretion (tablet): Urine (47-57%); feces (35-41%)

            Excretion (PO suspension): Urine



            Oral Administration

            Take with or without food; take consistently with respect to food


            Tablet: Store below 77°F (25°C)

            PO suspension: Store at 68-77°F (20-25°C); excursions permitted to 59-86°F (15-30°C); shake well before use, dispense in a tight container as defined in the USP





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            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
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