Drug interactions
Calcium + Erdafitinib
Severity: Moderate
Calcium and Erdafitinib: 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
Erdafitinib raises serum phosphate as an expected effect of FGFR inhibition, and the phosphate level is used to decide whether the dose should be increased. Calcium-based phosphate binders can lower phosphate and hide this signal, leading to incorrect dose decisions.
What this interaction means in plain words
Calcium and Erdafitinib 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.
Calcium belongs to Gastrointestinal Tract; Erdafitinib belongs to Oncology.
Why it happens
Calcium acetate binds dietary phosphate in the gut, pharmacodynamically masking the phosphate rise that guides erdafitinib dose titration.
What to do
Avoid phosphate binders containing calcium during the first 21 days of erdafitinib while phosphate-guided titration is being established. If a binder is later required, monitor serum phosphate closely and interpret it with the binder in mind.
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 Calcium
- Calcium + Ceftriaxone Contraindicated
- Acalabrutinib + Calcium Moderate
- Alendronate + Calcium Moderate
- Atazanavir + Calcium Moderate
- Baloxavir marboxil + Calcium Moderate
- Bendroflumethiazide + Calcium Moderate
Other interactions of Erdafitinib
Frequently asked questions
Can I take Calcium with Erdafitinib?
MediHelp rates the interaction as moderate. Calcium and Erdafitinib 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. Erdafitinib raises serum phosphate as an expected effect of FGFR inhibition, and the phosphate level is used to decide whether the dose should be increased. Calcium-based phosphate binders can lower phosphate and hide this signal, leading to incorrect dose decisions.
How serious is the interaction between Calcium and Erdafitinib?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid phosphate binders containing calcium during the first 21 days of erdafitinib while phosphate-guided titration is being established. If a binder is later required, monitor serum phosphate closely and interpret it with the binder in mind.
What other medicines interact with Calcium?
MediHelp also lists interactions of Calcium with, for example, Ceftriaxone, Acalabrutinib, Alendronate. The full list is on the Calcium page.
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