What the FDA labels say about taking them together
Potassium chloride and spironolactone
Potassium chloride's FDA label of July 14, 2025 names spironolactone in its contraindications section; spironolactone's label does not name potassium chloride itself but warns about its class (potassium salts). The potassium chloride label: “Hyperkalemia may complicate any of the following conditions: chronic renal failure, systemic acidosis, such as diabetic acidosis, acute dehydration, extensive tissue breakdown as in severe burns, adrenal insufficiency …”
Check it at the source: the potassium chloride FDA label on DailyMed (effective July 14, 2025, Upsher-Smith Laboratories, LLC); the spironolactone FDA label on DailyMed (effective November 28, 2025, Pfizer Laboratories Div Pfizer Inc).
What does the potassium chloride label say about spironolactone?
Potassium chloride label, contraindicationsHyperkalemia may complicate any of the following conditions: chronic renal failure, systemic acidosis, such as diabetic acidosis, acute dehydration, extensive tissue breakdown as in severe burns, adrenal insufficiency, or the administration of a potassium-sparing diuretic (e.g., spironolactone, triamterene, or amiloride) [see OVERDOSAGE ].
Potassium chloride label, warningsInteraction with Potassium-Sparing Diuretics Hypokalemia should not be treated by the concomitant administration of potassium salts and a potassium-sparing diuretic (e.g., spironolactone, triamterene, or amiloride) since the simultaneous administration of these agents can produce severe hyperkalemia.
Klor-Con label (Upsher-Smith Laboratories, LLC, July 14, 2025), drug interactionsDrugs that inhibit the renin-angiotensin-aldosterone system (RAAS) including angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), spironolactone, eplerenone, or aliskiren produce potassium retention by inhibiting aldosterone production.
Source: FDA drug label (Klor-Con, NDA019123), Upsher-Smith Laboratories, LLC, effective July 14, 2025 (SPL set 1ff53330-065c-4213-9c0c-ac498621d09d), via openFDA
Source: FDA drug label (KLOR-CON M), Upsher-Smith Laboratories, LLC, effective July 14, 2025 (SPL set b89910f6-4ff5-4a62-8269-696f7c10e4f6), via openFDA; the full label on DailyMed
What does the spironolactone label say about potassium chloride?
Spironolactone's label does not name potassium chloride itself; it warns about its class (potassium salts):
Spironolactone label, warnings and precautionsThis risk is increased by impaired renal function or concomitant potassium supplementation, potassium-containing salt substitutes or drugs that increase potassium, such as angiotensin converting enzyme inhibitors and angiotensin receptor blockers [see Drug Interactions (7.1) ].
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
| Potassium chloride | Spironolactone | |
|---|---|---|
| Labeled for | n/a | Heart failure, Edema (fluid retention), High blood pressure |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.0828 per tablet 10 mEq tablet | $0.0426 per tablet 25 mg tablet |
| Shortage now | A presentation being discontinued | 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