What the FDA labels say about taking them together
Cosyntropin and spironolactone
Cosyntropin's FDA label of January 30, 2025 names spironolactone in its drug interactions section; the spironolactone labels PlainMeds reads (2) do not name cosyntropin. The cosyntropin label: “Glucocorticoids and spironolactone may result in falsely elevated cortisol levels.”
Check it at the source: the cosyntropin FDA label on DailyMed (effective January 30, 2025, Amphastar Pharmaceuticals, Inc.); the spironolactone FDA label on DailyMed (effective November 28, 2025, Pfizer Laboratories Div Pfizer Inc).
What does the cosyntropin label say about spironolactone?
Cosyntropin label, drug interactionsDRUG INTERACTIONS Drug effects on plasma cortisol levels: ◦ Accuracy of the test results can be affected by concomitant medications. ◦ Glucocorticoids and spironolactone:
Cosyntropin label, warnings and precautionsGlucocorticoids and spironolactone may result in falsely elevated cortisol levels.
Source: FDA drug label (Cortrosyn), Amphastar Pharmaceuticals, Inc., effective January 30, 2025 (SPL set 746856e9-3930-4f6a-b8e6-a03845d6dd0b), via openFDA; the full label on DailyMed
What does the spironolactone label say about cosyntropin?
Spironolactone's label (effective November 28, 2025) and its 1 other brand-application label do not name cosyntropin in these sections. A label lists what its studies and reports found; it is not a complete list.
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
| Cosyntropin | Spironolactone | |
|---|---|---|
| Labeled for | n/a | Heart failure, Edema (fluid retention), High blood pressure |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | n/a | $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