Prescription medication · Potassium-Sparing Diuretic / Aldosterone Antagonist
spironolactone
Also sold as Aldactone. Spironolactone is used to treat heart failure by reducing fluid build-up and helping you live longer.
Data updated 2026-05-15
- 133,996
- FDA reportsHeavily reported
- 23
- InteractionsSeveral interactions
- In shortage
- FDA status
What the data shows
spironolactone (Aldactone) is a prescription Potassium-Sparing Diuretic / Aldosterone Antagonist, more reported than roughly 9 in 10 tracked drugs (133,996 FDA reports), with 23 documented drug interactions.
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
spironolactone (Aldactone) is a prescription Potassium-Sparing Diuretic / Aldosterone Antagonist. Spironolactone is used to treat heart failure by reducing fluid build-up and helping you live longer.
Spironolactone is a medicine that helps remove extra fluid from your body and lower blood pressure. It also helps your heart work better if you have heart failure.
Verify with FDA → · CMS NADAC pricing →
Drug Shortage Alert
spironolactone is currently listed as to be discontinued by the FDA. Affected manufacturer: Pfizer Inc..
View all drug shortages →Drug Pricing (NADAC)
Generic Price
$0.16/unit
Generic Available
Yes (14 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Spironolactone is used to treat heart failure by reducing fluid build-up and helping you live longer.
Common side effects
Breast enlargement in men, Dizziness, Headache
Key warnings
Spironolactone can cause your potassium levels to get too high, which can be dangerous.
The sections below are summarized in plain English from spironolactone's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Spironolactone belongs to a class of drugs called aldosterone antagonists. It works by blocking the effects of aldosterone, a hormone that causes your body to hold onto salt and water. By blocking aldosterone, spironolactone helps your body get rid of extra fluid and salt, which lowers blood pressure and reduces strain on the heart.
How to Take It
Take spironolactone exactly as your doctor tells you. You can take it with or without food, but try to take it the same way each time. For heart failure, you might start with 25 mg once a day. For high blood pressure, you might start with 25 mg to 100 mg each day, either as one dose or split into two doses. For fluid retention, you may need to start this medicine in the hospital.
This is a plain-language summary of spironolactone's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.
Pregnancy & Breastfeeding
Spironolactone may affect the sex organs of a baby boy if taken during pregnancy. Talk to your doctor if you are pregnant or plan to become pregnant. It is not known if spironolactone passes into breast milk, so talk to your doctor about the best way to feed your baby if you are taking this medicine.
This is a plain-language summary of spironolactone's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule.
This is a plain-language summary of spironolactone's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.
Storage
Store spironolactone at room temperature, away from light and moisture.
Side Effects (from patient reports)
Based on 133,996 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for spironolactone, by number of reports
- Difficulty breathing
Difficulty breathing
10,389 reports
- Tiredness
Tiredness
8,179 reports
- Feeling sick to your stomach
Feeling sick to your stomach
7,818 reports
- Loose stools
Loose stools
7,416 reports
- Sudden kidney damage
Sudden kidney damage
6,785 reports
- Feeling lightheaded
Feeling lightheaded
6,237 reports
- Pain in your head
Pain in your head
5,860 reports
- Low blood pressure
Low blood pressure
5,818 reports
- Accidentally falling down
Accidentally falling down
5,093 reports
- Weakness
Weakness
4,988 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for spironolactone each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where spironolactone sits
spironolactone has more FDA adverse-event reports than 91% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is spironolactone; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 133,996 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2001–2025.
Total Reports
133,996
Reports Mentioning Death
17,638
13.2% of reports — not proof of cause
Hospitalization Reports
64,112
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | DYSPNOEA | 10,389 |
| 2 | FATIGUE | 8,178 |
| 3 | NAUSEA | 7,818 |
| 4 | DIARRHOEA | 7,418 |
| 5 | ACUTE KIDNEY INJURY | 6,785 |
| 6 | DIZZINESS | 6,238 |
| 7 | HEADACHE | 5,859 |
| 8 | HYPOTENSION | 5,819 |
| 11 | FALL | 5,094 |
| 12 | ASTHENIA | 4,987 |
| 13 | HYPERKALAEMIA | 4,929 |
| 14 | DEATH | 4,916 |
| 15 | VOMITING | 4,849 |
| 16 | CARDIAC FAILURE | 4,485 |
| 17 | PNEUMONIA | 4,410 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Spironolactone can cause your potassium levels to get too high, which can be dangerous. Your doctor will check your potassium levels regularly, especially if you have kidney problems or are taking other medicines that can raise potassium. This medicine can also cause low blood pressure or make kidney problems worse. Tell your doctor if you have side effects.
Known Drug Interactions
Lithium: Increased risk of lithium toxicity ( 7.2 ). Examples of drugs that can increase potassium include: ACE inhibitors angiotensin receptor blockers non-steroidal anti-inflammatory drugs (NSAIDs) heparin and low molecular weight heparin trimethoprim 7.2 Lithium Like other diuretics, spironolactone reduces the renal clearance of lithium, thus increasing the risk of lithium toxicity. Monitor lithium levels periodically when spironolactone is co-administered [see Clinical Pharmacology (12.3) ] .
Mechanism: Spironolactone makes it harder for the kidneys to remove lithium from the body. This can cause lithium to build up to dangerous levels.
What to do: Your doctor should check your lithium blood levels regularly while you are taking both medications.
Examples of drugs that can increase potassium include: ACE inhibitors angiotensin receptor blockers non-steroidal anti-inflammatory drugs (NSAIDs) heparin and low molecular weight heparin trimethoprim 7.2 Lithium Like other diuretics, spironolactone reduces the renal clearance of lithium, thus increasing the risk of lithium toxicity.
Mechanism: Both of these medications can cause your body to hold onto potassium. Taking them together increases the risk of having too much potassium in your blood.
What to do: Your doctor may need to monitor your potassium levels closely or adjust your doses.
Examples of drugs that can increase potassium include: ACE inhibitors angiotensin receptor blockers non-steroidal anti-inflammatory drugs (NSAIDs) heparin and low molecular weight heparin trimethoprim 7.2 Lithium Like other diuretics, spironolactone reduces the renal clearance of lithium, thus increasing the risk of lithium toxicity.
Mechanism: Both drugs can raise the amount of potassium in your blood. Using them at the same time makes it more likely that your potassium levels will become too high.
What to do: Your healthcare provider should monitor your blood potassium levels frequently during treatment.
Potassium-sparing diuretics (spironolactone, amiloride, triamterene, and others) or potassium supplements can increase the risk of hyperkalemia. Potassium-sparing diuretics (spironolactone, amiloride, triamterene, and others) or potassium supplements can increase the risk of hyperkalemia.
Mechanism: Both of these medications can cause your body to hold onto potassium instead of flushing it out. This can lead to dangerously high levels of potassium in your blood.
What to do: Your doctor may need to check your blood potassium levels often or adjust your doses.
Hyperkalemia Potassium-sparing diuretics (spironolactone, amiloride, triamterene, and others) can increase the risk of hyperkalemia.
Mechanism: Both of these medicines cause the body to hold onto potassium instead of getting rid of it through urine. This can lead to a dangerous buildup of potassium in your blood.
What to do: Your doctor should monitor your blood potassium levels closely while you are taking this combination.
This is a plain-language summary of interactions documented in FDA labeling, not individualized advice. Ask a pharmacist or prescriber before combining medications.
Common Questions
Can I take spironolactone with food?
What should I do if I experience dizziness while taking spironolactone?
Will spironolactone affect my ability to drive?
How long does it take for spironolactone to start working?
Can spironolactone cause any changes in my period?
Does spironolactone interact with other medications?
Can I drink alcohol while taking spironolactone?
Will I need blood tests while taking spironolactone?
Can spironolactone cause breast enlargement in men?
What do the numbers on my pills mean?
What are the common side effects of spironolactone?
Does spironolactone interact with other medications?
What drug class is spironolactone?
Is spironolactone safe during pregnancy?
Has spironolactone been recalled?
Is spironolactone currently in shortage?
Active Recalls
Presence of foreign substance: identified as aluminum.
SUN PHARMACEUTICAL INDUSTRIES INC
Labeling: Label Mix-Up - Prepackaged bottles labeled spironolactone 50 mg may contain spironolactone 25 mg tablets.
Bryant Ranch Prepack, Inc. dba BRP Pharmaceuticals
Related Medications in Potassium-Sparing Diuretic / Aldosterone Antagonist
Other drugs grouped near spironolactone - same-class peers and common alternatives.
adenosine
Adenocard
Adenosine (Adenocard) is a medicine used to treat certain types of irregular heartbeats.
Compare with spironolactone →
amiodarone
Cordarone, Pacerone
Amiodarone (Pacerone) is a medicine used to treat life-threatening, irregular heartbeats.
Compare with spironolactone →
atropine
AtroPen
Atropine is a medicine that can temporarily block severe effects on your body.
Compare with spironolactone →
bumetanide
Bumex
Bumetanide is a water pill (diuretic).
Compare with spironolactone →
carvedilol
Coreg
Carvedilol is a medicine that lowers blood pressure and helps your heart work better.
Compare with spironolactone →
Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
Why some drugs demand precise dosing and monitoring
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
Save on spironolactone
Compare prices and find discounts at pharmacies near you. Free coupons can save up to 80% on prescriptions.
Disclosure: This link may earn us a commission at no extra cost to you. See our terms.
What the FDA Data Shows for spironolactone
The FDA label for spironolactone (sold under brand names such as Aldactone) classifies it as a prescription-only medication in the Potassium-Sparing Diuretic / Aldosterone Antagonist class. Spironolactone is used to treat heart failure by reducing fluid build-up and helping you live longer. Official labeling lists 3 commonly reported side effects, including Breast enlargement in men, Dizziness, Headache.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 133,996 voluntary reports. The database also lists 23 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated moderate severity. NADAC pricing from CMS shows a generic unit cost of $0.16.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history (currently 2 recall records on file), and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice, always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC). Shortage status: FDA Drug Shortages Database.
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: January 13, 2025
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages