What the FDA labels say about taking them together
Olmesartan and spironolactone
Olmesartan's FDA label of September 23, 2025 names spironolactone in its drug interactions section; spironolactone's label does not name olmesartan itself but warns about its class (ARBs (angiotensin II receptor blockers)). The olmesartan label: “Concomitant use of olmesartan with other agents that block the renin-angiotensin system, potassium-sparing diuretics, potassium supplements, salt substitutes containing potassium or other drugs that may increase …”
Check it at the source: the olmesartan FDA label on DailyMed (effective September 23, 2025, Cosette Pharmaceuticals, Inc.); the spironolactone FDA label on DailyMed (effective November 28, 2025, Pfizer Laboratories Div Pfizer Inc).
What does the olmesartan label say about spironolactone?
Olmesartan label, drug interactionsConcomitant use of olmesartan with other agents that block the renin-angiotensin system, potassium-sparing diuretics (e.g., spironolactone, triamterene, amiloride), potassium supplements, salt substitutes containing potassium or other drugs that may increase potassium levels (e.g., heparin) may lead to increases in serum potassium.
Source: FDA drug label (Benicar), Cosette Pharmaceuticals, Inc., effective September 23, 2025 (SPL set dc3f1fd4-5578-4c5d-be7b-12e3f8f3e7df), via openFDA; the full label on DailyMed
What does the spironolactone label say about olmesartan?
Spironolactone's label does not name olmesartan itself; it warns about its class (ARBs (angiotensin II receptor blockers)):
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
| Olmesartan | Spironolactone | |
|---|---|---|
| Labeled for | High blood pressure | Heart failure, Edema (fluid retention), High blood pressure |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.0805 per tablet 20 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