Spironolactone

Generic Name: Spironolactone

Brand Names: Aldactone, CaroSpir

Spironolactone is a potassium-sparing diuretic and aldosterone antagonist used to treat heart failure, high blood pressure, and fluid retention. It is also used to treat hormonal acne and hirsutism in women.

CardiovascularDiureticsHeart FailureDermatologyHormonal

Drug Class

Aldosterone Receptor Antagonist (Potassium-Sparing Diuretic)

Pregnancy

Category C — Spironolactone has anti-androgenic activity that can theoretically feminize a male fetus; animal data support this concern. Generally avoided in pregnancy unless no alternative is suitable. Patients with reproductive potential using spironolactone for acne or hirsutism should use effective contraception.

Available Forms

Oral tablet (25 mg, 50 mg, 100 mg), Oral suspension (CaroSpir 25 mg/5 mL)

What It's Used For

is prescribed to treat:

• Heart failure (reduces mortality and hospitalizations) • High blood pressure (hypertension) • Edema (fluid retention) from various causes • Primary hyperaldosteronism • Cirrhosis with ascites • Nephrotic syndrome • Hormonal acne in women (off-label) • Polycystic ovary syndrome (PCOS) symptoms (off-label) • Hirsutism (excessive hair growth in women) (off-label)

It helps remove excess fluid while retaining potassium.

Dosage Quick Reference

These are general dosage guidelines. Your doctor will determine the appropriate dose for your specific situation.

Condition	Starting Dose	Maintenance Dose
Heart failure (HFrEF, NYHA Class II-IV)	12.5–25 mg orally once daily	25–50 mg once daily; monitor potassium and creatinine
Hypertension (resistant or as add-on)	25 mg orally once daily	25–100 mg/day in 1–2 divided doses
Edema (cirrhosis, nephrotic syndrome)	100 mg orally daily in single or divided doses	25–200 mg/day; titrate to clinical response
Primary hyperaldosteronism (preoperative or chronic)	100–400 mg orally daily	Titrate to potassium and blood pressure response
Hormonal acne or hirsutism (off-label, women)	25–50 mg orally daily	50–200 mg/day; benefit usually evident at 3–6 months

Side Effects

Common side effects may include:

• Increased urination • Dizziness or lightheadedness • Headache • Nausea or vomiting • Diarrhea or stomach cramps • Drowsiness • Irregular menstrual periods • Breast tenderness or enlargement (in both men and women)

Serious side effects (seek immediate medical attention):

• Signs of high potassium (muscle weakness, slow/irregular heartbeat, severe dizziness) • Severe dehydration (very dry mouth, extreme thirst, muscle cramps) • Signs of electrolyte imbalance • Severe allergic reactions • Unusual bleeding or bruising • Yellowing of skin or eyes (liver problems) • Confusion or mental changes

Drug Interactions

Spironolactone elevates potassium and modulates the renin-angiotensin-aldosterone system, producing several clinically critical interactions.

ACE inhibitors, ARBs, and direct renin inhibitors (e.g., lisinopril, losartan, aliskiren): Additive hyperkalemia risk that can be life-threatening, especially in patients with reduced kidney function or diabetes. Routinely monitor serum potassium and creatinine 1 week after initiation, after dose changes, and periodically thereafter.
Potassium supplements and salt substitutes containing potassium chloride: Avoid concurrent use unless serum potassium is closely monitored and clinically indicated (e.g., correcting documented hypokalemia).
NSAIDs (e.g., ibuprofen, naproxen, celecoxib): Reduce diuretic and antihypertensive efficacy and increase the risk of hyperkalemia and acute kidney injury. Use the lowest NSAID dose for the shortest duration when needed.
Digoxin: Spironolactone interferes with several digoxin assays and modestly raises digoxin levels. Monitor digoxin concentrations and clinical response.
Lithium: Reduced renal clearance can elevate lithium levels into the toxic range. Monitor lithium concentrations carefully.
Trimethoprim (including in TMP/SMX): Trimethoprim itself causes potassium retention and produces synergistic hyperkalemia with spironolactone, particularly in older adults. Several large studies have linked this combination to sudden death; avoid co-prescription when possible.

Additional Information

What is ?

Spironolactone is a unique medication that serves multiple purposes in medicine. Primarily classified as a potassium-sparing diuretic and aldosterone antagonist, it is used to treat heart failure, high blood pressure, and fluid retention. Additionally, due to its anti-androgenic properties, it is commonly prescribed off-label for hormonal acne and excess hair growth in women.

How Does Spironolactone Work?

Spironolactone has several mechanisms of action:

As an Aldosterone Antagonist:

Blocks aldosterone receptors in the kidneys
Reduces sodium and water retention
Prevents potassium loss
Reduces harmful cardiac remodeling in heart failure
Decreases fibrosis in various organs

As a Potassium-Sparing Diuretic:

Promotes excretion of sodium and water
Retains potassium (unlike thiazide or loop diuretics)
Mild diuretic effect compared to furosemide or hydrochlorothiazide

As an Anti-Androgen:

Blocks androgen receptors
Reduces effects of testosterone and DHT
Decreases sebum production (helpful for acne)
Reduces unwanted hair growth in women

Common Uses

Cardiovascular Uses

Heart Failure:

Reduces mortality by 30% in severe heart failure when added to standard therapy
Decreases hospitalizations
Improves quality of life
Used in heart failure with reduced ejection fraction (HFrEF)

Hypertension:

Particularly effective in resistant hypertension
Often used in combination with other blood pressure medications
Especially useful in primary hyperaldosteronism

Edema/Fluid Retention:

Cirrhosis with ascites
Nephrotic syndrome
Congestive heart failure

Dermatologic and Endocrine Uses (Often Off-Label)

Hormonal Acne in Women:

Particularly effective for adult female acne
Reduces sebum production
Often combined with oral contraceptives
May take 3-6 months to see full effects

Polycystic Ovary Syndrome (PCOS):

Manages symptoms of hirsutism
May help with acne
Can improve hormonal balance

Hirsutism:

Reduces excess facial and body hair in women
Effects gradual, may take 6+ months

Dosage and Administration

Dosing varies significantly based on the condition being treated:

For Heart Failure:

Starting dose: 12.5-25 mg once daily
Target dose: 25-50 mg once daily
Maximum: 50 mg daily

For Hypertension/Edema:

25-200 mg daily in 1-2 divided doses
Typical: 50-100 mg daily

For Acne/Hirsutism (Off-Label):

25-200 mg daily
Usually 50-100 mg daily for acne
Often taken with oral contraceptive

Administration Tips:

Can be taken with or without food (food may reduce stomach upset)
Take in the morning to avoid nighttime urination
If taking twice daily, take second dose in early afternoon
Take consistently at the same times each day
Avoid taking late in the day (increases nighttime urination)

Important Safety Information

Who Should Not Take Spironolactone?

Do not take spironolactone if you have:

High potassium levels (hyperkalemia)
Severe kidney disease or acute renal failure
Addison's disease
Anuria (inability to urinate)
Known allergy to spironolactone

Use with extreme caution if you have:

Kidney disease (moderate)
Liver disease
Diabetes
Electrolyte imbalances

Drug Interactions

Dangerous Interactions (Risk of High Potassium):

ACE inhibitors (lisinopril, enalapril)
ARBs (losartan, valsartan)
Potassium supplements
Salt substitutes containing potassium
Other potassium-sparing diuretics
NSAIDs (ibuprofen, naproxen)
Heparin
Trimethoprim

Other Important Interactions:

Lithium - may increase lithium levels
Digoxin - may alter digoxin levels
Cholestyramine - decreases absorption
NSAIDs - reduce effectiveness and increase potassium
Aspirin - may reduce effectiveness in heart failure

Pregnancy and Breastfeeding

Pregnancy Category C: Use only if benefit outweighs risk
Not recommended during pregnancy due to anti-androgenic effects
May feminize male fetus
Women of childbearing age often prescribed with contraceptives for acne/hirsutism
Enters breast milk - not recommended during breastfeeding

Monitoring and Follow-Up

Critical Monitoring:

Potassium Levels:

Check before starting
Recheck at 1 week, 1 month, then quarterly
Target: 3.5-5.0 mEq/L
Risk of hyperkalemia is main safety concern

Kidney Function:

Creatinine, BUN, eGFR
Monitor closely, especially with other medications affecting kidneys

Blood Pressure:

Regular monitoring
Home blood pressure checks recommended

Electrolytes:

Sodium, magnesium
Comprehensive metabolic panel

For Heart Failure Patients:

More frequent monitoring initially
Check at 3 days, 1 week, monthly for 3 months, then quarterly

Managing High Potassium Risk

To minimize hyperkalemia risk:

Avoid potassium supplements unless specifically prescribed
Avoid salt substitutes (most contain potassium)
Limit high-potassium foods (bananas, oranges, tomatoes, spinach, potatoes)
Monitor potassium levels regularly
Inform all doctors that you take spironolactone
Be cautious with NSAIDs
Report muscle weakness, palpitations, or tingling

For Women Taking for Acne/Hirsutism

Important Considerations:

Usually prescribed with birth control pills
Effective contraception is essential (can feminize male fetus)
Takes 3-6 months to see improvement in acne
Hair reduction effects gradual (6+ months)
May cause irregular periods if not taking with contraceptives
Breast tenderness common but usually temporary
Continue medication as directed even if side effects occur initially

Maximizing Benefits for Acne:

Be patient - improvement gradual
Continue good skincare routine
May be combined with topical treatments
Don't stop abruptly - acne may worsen

Side Effects and Management

Breast Tenderness/Enlargement (Gynecomastia)

Common due to anti-androgenic effects
More common at higher doses
Usually reversible upon stopping medication
May improve with time
Discuss with doctor if bothersome

Menstrual Irregularities

Common when not taking with contraceptives
Usually resolves with time
Report heavy or prolonged bleeding

Dizziness

Especially when standing up quickly (orthostatic hypotension)
Rise slowly from sitting or lying positions
Stay hydrated
More common when starting or increasing dose

Increased Urination

Expected effect as a diuretic
Usually improves after first few weeks
Time last dose to avoid nighttime disruption

Lifestyle Considerations

While taking spironolactone:

Stay hydrated but don't overdrink
Follow dietary potassium recommendations from your doctor
Avoid excessive sun exposure (may increase sensitivity)
Use sunscreen
Limit alcohol
Monitor weight for heart failure patients
Rise slowly to prevent dizziness
Avoid hot baths or prolonged standing

When to Contact Your Doctor

Seek immediate medical attention if you experience:

Signs of high potassium:
- Muscle weakness
- Slow or irregular heartbeat
- Tingling or numbness
- Chest pain
Severe dizziness or fainting
Severe dehydration
Difficulty breathing
Severe stomach pain
Dark urine or yellowing of skin/eyes
Unusual bleeding or bruising

Contact your doctor for routine issues:

Breast tenderness or enlargement that is bothersome
Persistent irregular periods (when not on contraceptives)
Questions about potassium in diet
New medications prescribed by other doctors
Persistent headache or nausea
Excessive tiredness

Long-Term Benefits

Clinical evidence shows spironolactone:

For Heart Failure:

Reduces mortality by 30% in severe heart failure
Decreases heart failure hospitalizations by 35%
Improves symptoms and quality of life
Reduces sudden cardiac death

For Hypertension:

Effective blood pressure control, especially resistant hypertension
Particularly useful when other medications inadequate

For Acne (Off-Label):

50-100% improvement in moderate to severe hormonal acne
Reduces oil production significantly
May allow discontinuation of oral antibiotics

Storage

Store spironolactone at room temperature (77°F/25°C) with excursions permitted to 59-86°F (15-30°C). Protect from light and moisture. Keep in tight, light-resistant container. Keep out of reach of children and pets.

Generic vs. Brand

Spironolactone is widely available as an affordable generic. Brand names include Aldactone and CaroSpir (oral suspension). Generic versions are bioequivalent and significantly less expensive.

Disclaimer: This information is for educational purposes only and is not intended to replace professional medical advice, diagnosis, or treatment. Always consult your physician or other qualified healthcare provider with any questions about a medical condition or medication.

Frequently Asked Questions

Spironolactone blocks androgen receptors in addition to aldosterone receptors. This anti-androgenic activity produces gynecomastia (breast tissue enlargement) in roughly 10% of men at typical doses, with higher rates at doses above 100 mg/day. The effect is generally reversible after discontinuation. Eplerenone is a more selective alternative for men in whom this side effect is unacceptable.

Most clinicians check potassium and creatinine at baseline, within 1 week of starting spironolactone, again at 1 month, and then every 3–6 months for stable patients. More frequent monitoring is warranted with concurrent ACE inhibitors or ARBs, kidney impairment, dose changes, or acute illness affecting fluid balance.

In women, hormonal acne is often driven by androgenic stimulation of sebaceous glands. Spironolactone blocks androgen receptors at the skin level, reducing sebum production and acne lesions over 3–6 months. It is typically used at 50–200 mg/day and is an effective alternative or adjunct to topical therapy, retinoids, and oral contraceptives.

Spironolactone is rarely prescribed to men because of its feminizing effects, including gynecomastia, decreased libido, and erectile dysfunction. For male androgenic alopecia, finasteride is the preferred anti-androgen. For acne in men, isotretinoin or other systemic therapies are usually selected.

You do not need to avoid normal dietary potassium, but excessive intake — large amounts of bananas, oranges, tomatoes, potatoes, or salt substitutes containing potassium chloride — should be avoided. Discuss your diet with your provider and have your potassium monitored as recommended.

Questions to Ask Your Doctor

Consider discussing these topics at your next appointment:

✓How often will my potassium and kidney function be checked while I am on spironolactone?
✓Are any of my other medications likely to interact with spironolactone to raise my potassium?
✓What symptoms of high potassium should make me call you immediately?
✓For long-term use, what would prompt us to switch to eplerenone or another agent?
✓How will we know whether spironolactone is achieving the goal we set — better blood pressure, fluid control, or skin response?

Schedule an Appointment

Related Health Conditions

This medication is commonly used to treat or manage the following conditions:

Acne

Acne vulgaris, a chronic inflammatory skin condition, arises from clogged hair follicles due to excess sebum, dead skin cells, bacteria, hormones, genetics, diet, stress, or medications.

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Atrial Fibrillation

Atrial fibrillation, a common arrhythmia characterized by rapid, irregular heartbeats, increases risk of stroke and heart failure, often linked to age, hypertension, and heart disease.

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Attention Deficit Hyperactivity Disorder (ADHD)

ADHD is a neurodevelopmental disorder marked by inattention, hyperactivity, and/or impulsivity, stemming from complex interactions between genetics, brain differences, and environmental factors, not poor parenting.

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Cirrhosis

Cirrhosis is irreversible, late-stage liver disease where scar tissue replaces healthy tissue, impairing its vital functions like filtering toxins and often caused by alcohol abuse or hepatitis.

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Heart Failure Due to Coronary Artery Disease

Heart failure stemming from coronary artery disease arises from narrowed arteries restricting blood flow, weakening or stiffening the heart muscle and reducing its pumping efficiency.

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Hives (Urticaria)

Hives (urticaria) are itchy, raised welts caused by histamine release, triggered by allergens, physical stimuli, medications, infections, stress, or sometimes, unknown factors.

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Portal Hypertension

Portal hypertension, an elevated pressure in the portal vein due to blockage often from cirrhosis or other pre-hepatic causes, can lead to serious complications like bleeding and ascites.

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Secondary Pulmonary Hypertension

Secondary pulmonary hypertension, unlike its primary form, arises from underlying conditions such as heart/lung disease, blood clots, or connective tissue disorders, increasing lung artery pressure.

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Vertigo

Vertigo, a spinning sensation distinct from dizziness, often stems from inner ear or brain issues like BPPV or Meniere's, sometimes triggered by head trauma or medication.

Learn More

Medical Disclaimer: This information is for educational purposes only and should not be considered medical advice. Always consult with your healthcare provider before starting, stopping, or changing any medication. Your doctor can provide personalized recommendations based on your specific health condition and medical history.