Drug interactions
Fludrocortisone + Phenobarbital
Severity: Moderate
Fludrocortisone and Phenobarbital: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Phenobarbital induces CYP3A4 and possibly P-glycoprotein, which can lower corticosteroid levels and weaken the effect of fludrocortisone. Patients with adrenal insufficiency may develop hypotension, hyponatremia or hyperkalemia if replacement becomes inadequate.
What this interaction means in plain words
Fludrocortisone and Phenobarbital can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Enzyme induction of CYP3A4 and P-glycoprotein by phenobarbital, increasing corticosteroid clearance.
What to do
Monitor blood pressure, electrolytes and symptoms of adrenal insufficiency, and raise the fludrocortisone dose if needed. Reassess the dose if phenobarbital is stopped.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Fludrocortisone
Frequently asked questions
Can I take Fludrocortisone with Phenobarbital?
MediHelp rates the interaction as moderate. Fludrocortisone and Phenobarbital can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Phenobarbital induces CYP3A4 and possibly P-glycoprotein, which can lower corticosteroid levels and weaken the effect of fludrocortisone. Patients with adrenal insufficiency may develop hypotension, hyponatremia or hyperkalemia if replacement becomes inadequate.
How serious is the interaction between Fludrocortisone and Phenobarbital?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood pressure, electrolytes and symptoms of adrenal insufficiency, and raise the fludrocortisone dose if needed. Reassess the dose if phenobarbital is stopped.
What other medicines interact with Fludrocortisone?
MediHelp also lists interactions of Fludrocortisone with, for example, Mifepristone, Aldesleukin, Amphotericin b. The full list is on the Fludrocortisone page.
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