Drug interactions
Ergocalciferol + Primidone
Severity: Moderate
Ergocalciferol and Primidone: 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
Long-term primidone use, partly through its conversion to phenobarbital, increases vitamin D breakdown and can cause vitamin D deficiency and bone disease. Standard supplement doses may be less effective.
What this interaction means in plain words
Ergocalciferol and Primidone 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.
Ergocalciferol belongs to Musculoskeletal; Primidone belongs to Central Nervous System.
Why it happens
Primidone and its metabolite phenobarbital induce hepatic CYP enzymes, accelerating vitamin D catabolism.
What to do
Monitor 25-hydroxyvitamin D, calcium and bone health in chronic users, and raise vitamin D dosing when levels are low.
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 Ergocalciferol
- Aluminum hydroxide + Ergocalciferol Moderate
- Calcium acetate + Ergocalciferol Moderate
- Calcium carbonate + Ergocalciferol Moderate
- Calcium chloride + Ergocalciferol Moderate
- Calcium citrate + Ergocalciferol Moderate
- Calcium gluconate + Ergocalciferol Moderate
Other interactions of Primidone
- Lorlatinib + Primidone Contraindicated
- Lurasidone + Primidone Contraindicated
- Primidone + Ranolazine Contraindicated
- Primidone + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
- Primidone + Voriconazole Contraindicated
- Abiraterone + Primidone Major
Frequently asked questions
Can I take Ergocalciferol with Primidone?
MediHelp rates the interaction as moderate. Ergocalciferol and Primidone 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. Long-term primidone use, partly through its conversion to phenobarbital, increases vitamin D breakdown and can cause vitamin D deficiency and bone disease. Standard supplement doses may be less effective.
How serious is the interaction between Ergocalciferol and Primidone?
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, calcium and bone health in chronic users, and raise vitamin D dosing when levels are low.
What other medicines interact with Ergocalciferol?
MediHelp also lists interactions of Ergocalciferol with, for example, Aluminum hydroxide, Calcium acetate, Calcium carbonate. The full list is on the Ergocalciferol page.
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