spironolactone
Brand names: Aldactone
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.
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.
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.
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.
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.
Storage
Store spironolactone at room temperature, away from light and moisture.
Side Effects (from patient reports)
Based on 69,263 FDA adverse event reports.
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
Death-Related Reports
17,638
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 |
| 9 | OFF LABEL USE | 5,556 |
| 10 | DRUG INEFFECTIVE | 5,205 |
| 11 | FALL | 5,094 |
| 12 | ASTHENIA | 4,987 |
| 13 | HYPERKALAEMIA | 4,929 |
| 14 | DEATH | 4,916 |
| 15 | VOMITING | 4,849 |
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.
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
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Medication Guides
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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 69,263 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.
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