What the FDA labels say about taking them together
Captopril and spironolactone
Captopril's FDA label of February 6, 2026 names spironolactone in its drug interactions section; spironolactone's label does not name captopril itself but warns about its class (ACE inhibitors). The captopril label: “Potassium-sparing diuretics such as spironolactone, triamterene, or amiloride, or potassium supplements should be given only for documented hypokalemia, and then with caution, since they may lead to a significant …”
Check it at the source: the captopril FDA label on DailyMed (effective February 6, 2026, AiPing Pharmaceutical, Inc.); the spironolactone FDA label on DailyMed (effective November 28, 2025, Pfizer Laboratories Div Pfizer Inc).
What does the captopril label say about spironolactone?
Captopril label, drug interactionsPotassium-sparing diuretics such as spironolactone, triamterene, or amiloride, or potassium supplements should be given only for documented hypokalemia, and then with caution, since they may lead to a significant increase of serum potassium.
Source: FDA drug label (Captopril), AiPing Pharmaceutical, Inc., effective February 6, 2026 (SPL set 3b789f16-b291-4012-be39-af3beec3ff9a), via openFDA; the full label on DailyMed
What does the spironolactone label say about captopril?
Spironolactone's label does not name captopril itself; it warns about its class (ACE inhibitors):
Spironolactone label, warnings and precautionsExcessive diuresis may cause symptomatic dehydration, hypotension and worsening renal function, particularly in salt-depleted patients or those taking angiotensin converting enzyme inhibitors and angiotensin II receptor blockers.
Spironolactone label, drug interactionsIn general, discontinue potassium supplementation in heart failure patients who start ALDACTONE [see Warnings and Precautions (5.1) and Clinical Pharmacology (12.3) ]. Check serum potassium levels when ACE inhibitor or ARB therapy is altered in patients receiving ALDACTONE.
Source: FDA drug label (Aldactone), Pfizer Laboratories Div Pfizer Inc, effective November 28, 2025 (SPL set 0fed2822-3a03-4b64-9857-c682fcd462bc), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Captopril | Spironolactone | |
|---|---|---|
| Labeled for | High blood pressure, Heart failure, Chronic kidney disease | Heart failure, Edema (fluid retention), High blood pressure |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.228 per tablet 12.5 mg tablet | $0.0426 per tablet 25 mg tablet |
| Shortage now | No current entry | A presentation being discontinued |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once