Fludrocortisone and Natalizumab interaction

Fludrocortisone and Natalizumab: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.

Major

Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.

What the FDA labels say

From the Fludrocortisone (Fludrocortisone Acetate) label · effective 2026-05-06

Major

Chicken pox and measles, for example, can have a more serious or even fatal course in children on immunosuppressant corticosteroids.

Warningsby drug classView label on DailyMed
Major

Patients who are on immunosuppressant doses of corticosteroids should be warned to avoid exposure to chicken pox or measles and, if exposed, to obtain medical advice.

Precautionsby drug classView label on DailyMed
Minor

Children who are on immunosuppressant drugs are more susceptible to infections than healthy children.

Warningsby drug classView label on DailyMed

From the Natalizumab (TYRUKO) label · effective 2025-10-31

Moderate

In Studies MS1 and MS2, an increase in infections was seen in patients concurrently receiving short courses of corticosteroids.

Warnings and precautionsby drug classView label on DailyMed
Moderate

However, the increase in infections in natalizumab-treated patients who received steroids was similar to the increase in placebo-treated patients who received steroids.

Warnings and precautionsby drug classView label on DailyMed
Moderate

In Studies CD1 and CD2, an increase in infections was seen in patients concurrently receiving corticosteroids.

Warnings and precautionsby drug classView label on DailyMed
Moderate

However, the increase in infections was similar in placebo-treated and natalizumab-treated patients who received steroids.

Warnings and precautionsby drug classView label on DailyMed
Moderate

…receiving natalizumab products should not be treated with concomitant immunosuppressants (e.g., 6‑ mercaptopurine, azathioprine, cyclosporine, or methotrexate) or inhibitors of TNF-α, and corticosteroids should be tapered in those patients with Crohn’s disease who are on chronic corticosteroids when they start TYRUKO therapy [see Indications and Usage ( 1.2 ) and Warnings…

Drug interactionsby drug classView label on DailyMed

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Not medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.