Hydrochlorothiazide and Fludrocortisone Acetate: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Hydrochlorothiazide
Fludrocortisone Acetate
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Hypokalemia and subsequent cardiac arrhythmias
Interaction Deep Dive
Concurrent thiazide diuretic and corticosteroid therapy has been reported to result in excessive potassium loss21.
Why it happens (mechanism)
Additive hypokalemic effects
Common questions
Can I take Hydrochlorothiazide and Fludrocortisone Acetate together?
Hypokalemia and subsequent cardiac arrhythmias Always confirm with your pharmacist or prescriber before making any change.
How serious is the Hydrochlorothiazide and Fludrocortisone Acetate interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Hydrochlorothiazide or Fludrocortisone Acetate need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (2)
- Thorn GW: Clinical considerations in the use of corticosteroids. N Engl J Med 1966; 274:775. PubMed
- Anon: Adverse interactions of drugs. Med Lett Drugs Ther 1981; 23:17-28.
Keep reading about Hydrochlorothiazide
Keep reading about Fludrocortisone Acetate
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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