Drug interactions
Cholecalciferol + Fosphenytoin
Severity: Moderate
Cholecalciferol 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
Chronic phenytoin therapy accelerates vitamin D metabolism and may lead to vitamin D deficiency and reduced bone density. Fosphenytoin is converted to phenytoin, so the same risk applies.
What this interaction means in plain words
Cholecalciferol 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.
Cholecalciferol belongs to Musculoskeletal; Fosphenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces hepatic CYP enzymes, increasing the catabolism of vitamin D.
What to do
Monitor 25-hydroxyvitamin D and bone health in long-term users. Supplement vitamin D at higher doses if deficient.
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 Cholecalciferol
- Cholecalciferol + Digoxin Major
- Aluminum hydroxide + Cholecalciferol Moderate
- Calcium acetate + Cholecalciferol Moderate
- Calcium Carbonate + Cholecalciferol Moderate
- Calcium chloride + Cholecalciferol Moderate
- Calcium citrate + Cholecalciferol 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 Cholecalciferol with Fosphenytoin?
MediHelp rates the interaction as moderate. Cholecalciferol 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. Chronic phenytoin therapy accelerates vitamin D metabolism and may lead to vitamin D deficiency and reduced bone density. Fosphenytoin is converted to phenytoin, so the same risk applies.
How serious is the interaction between Cholecalciferol 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 25-hydroxyvitamin D and bone health in long-term users. Supplement vitamin D at higher doses if deficient.
What other medicines interact with Cholecalciferol?
MediHelp also lists interactions of Cholecalciferol with, for example, Digoxin, Aluminum hydroxide, Calcium acetate. The full list is on the Cholecalciferol page.
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