Spironolactone
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.
About Spironolactone
Spironolactone is an aldosterone receptor antagonist (potassium-sparing diuretic) also sold under brand names including Aldactone and CaroSpir. It is primarily used to 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. Spironolactone is available in oral tablet (25 mg, 50 mg, 100 mg) and oral suspension (carospir 25 mg/5 ml) form. Healthcare providers commonly prescribe Spironolactone for conditions including Acne, Atrial Fibrillation, Attention Deficit Hyperactivity Disorder (ADHD), and Cirrhosis.
Spironolactone at a Glance
- Brand names
- Aldactone, CaroSpir
- Drug class
- Aldosterone Receptor Antagonist (Potassium-Sparing Diuretic)
- Pregnancy category
- FDA Category 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)
- Therapeutic categories
- Cardiovascular, Diuretics, Heart Failure, Dermatology, Hormonal
- Conditions treated
- 9 related conditions on this site
What Spironolactone Is 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 for Spironolactone. 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
See also: Drug Interactions ↓
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.
See also: Questions to Ask Your Doctor ↓
Key Considerations
Known drug interactions
Spironolactone has documented interactions with other medications, supplements, and certain foods. Review the Drug Interactions section below and tell your healthcare provider about every medication you take, including over-the-counter products. Jump to section →
Multiple forms available
Spironolactone comes in more than one form (Oral tablet (25 mg, 50 mg, 100 mg), Oral suspension (CaroSpir 25 mg/5 mL)). The right form for you depends on your condition, ease of use, and your provider's recommendation.
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)
- 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
Questions to Ask Your Doctor About Spironolactone
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?
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.