Drug interactions
Cinacalcet + Fosphenytoin
Severity: Moderate
Cinacalcet and Fosphenytoin: 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
Phenytoin, formed from fosphenytoin, induces CYP3A4 and may lower cinacalcet concentrations. Calcium and PTH control may worsen as a result.
What this interaction means in plain words
Cinacalcet and Fosphenytoin 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.
Cinacalcet belongs to Miscellaneous; Fosphenytoin belongs to Central Nervous System.
Why it happens
Enzyme induction of CYP3A4 increases cinacalcet clearance.
What to do
Monitor serum calcium and PTH after starting or stopping fosphenytoin. Adjust the cinacalcet dose according to response.
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 Cinacalcet
- Cinacalcet + Etelcalcetide Contraindicated
- Cinacalcet + Eliglustat Major
- Cinacalcet + Metoclopramide Major
- Cinacalcet + Metoclopramide intranasal Major
- Cinacalcet + Tamoxifen Major
- Abiraterone + Cinacalcet Moderate
Other interactions of Fosphenytoin
- Dronedarone + Fosphenytoin Contraindicated
- Fosphenytoin + Ledipasvir-sofosbuvir Contraindicated
- Fosphenytoin + Lorlatinib Contraindicated
- Fosphenytoin + Lurasidone Contraindicated
- Fosphenytoin + Ranolazine Contraindicated
- Fosphenytoin + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
Frequently asked questions
Can I take Cinacalcet with Fosphenytoin?
MediHelp rates the interaction as moderate. Cinacalcet and Fosphenytoin 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. Phenytoin, formed from fosphenytoin, induces CYP3A4 and may lower cinacalcet concentrations. Calcium and PTH control may worsen as a result.
How serious is the interaction between Cinacalcet and Fosphenytoin?
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 serum calcium and PTH after starting or stopping fosphenytoin. Adjust the cinacalcet dose according to response.
What other medicines interact with Cinacalcet?
MediHelp also lists interactions of Cinacalcet with, for example, Etelcalcetide, Eliglustat, Metoclopramide. The full list is on the Cinacalcet page.
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