What the FDA labels say about taking them together
Heparin and hydrochlorothiazide/spironolactone
Hydrochlorothiazide/spironolactone's FDA label of March 11, 2026 names heparin in its drug interactions section; the heparin labels PlainMeds reads (4) do not name hydrochlorothiazide/spironolactone. The hydrochlorothiazide/spironolactone label: “Drug interactions ACE inhibitors, Angiotensin II receptor antagonists, aldosterone blockers, potassium supplements, heparin, low molecular weight heparin, and other drugs known to cause hyperkalemia:”
Check it at the source: the heparin FDA label on DailyMed (effective November 28, 2025, Fresenius Kabi USA, LLC); the hydrochlorothiazide/spironolactone FDA label on DailyMed (effective March 11, 2026, Mylan Pharmaceuticals Inc.).
What does the heparin label say about hydrochlorothiazide/spironolactone?
Heparin's label (effective November 28, 2025) and its 3 other brand-application labels do not name hydrochlorothiazide/spironolactone in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Heparin Sodium), Fresenius Kabi USA, LLC, effective November 28, 2025 (SPL set d55b4a63-0c04-4874-b74f-9e9b9e8b008c), via openFDA; the full label on DailyMed
What does the hydrochlorothiazide/spironolactone label say about heparin?
Hydrochlorothiazide/spironolactone label, drug interactionsDrug interactions ACE inhibitors, Angiotensin II receptor antagonists, aldosterone blockers, potassium supplements, heparin, low molecular weight heparin, and other drugs known to cause hyperkalemia Concomitant administration may lead to severe hyperkalemia.
Hydrochlorothiazide/spironolactone label, warningsheparin and low molecular weight heparin
Source: FDA drug label (Spironolactone And Hydrochlorothiazide, NDA012616), Prasco Laboratories, effective February 10, 2026 (SPL set 9d350fa2-d568-4970-a7a5-d128ff5d0a2f), via openFDA
Source: FDA drug label (Spironolactone and Hydrochlorothiazide), Mylan Pharmaceuticals Inc., effective March 11, 2026 (SPL set 0c8c973f-13a2-4883-8316-4006398e2931), 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
| Heparin | Hydrochlorothiazide/spironolactone | |
|---|---|---|
| Labeled for | Blood clots (DVT and PE), Atrial fibrillation | Heart failure, Edema (fluid retention), High blood pressure |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $1.18 per mL 5,000 unit/mL vial | $0.483 per tablet 25-25 tablet |
| Shortage now | In shortage | No current entry |
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