Drug interactions
Primidone + Tacrolimus
Severity: Major
Primidone and Tacrolimus: major interaction.
Last updated Sources: UK SmPC
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
Primidone is metabolized to phenobarbital, a potent enzyme inducer that can substantially lower tacrolimus concentrations. This risks subtherapeutic immunosuppression and graft rejection in transplant recipients.
What this interaction means in plain words
Primidone and Tacrolimus can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Primidone belongs to Central Nervous System; Tacrolimus belongs to Miscellaneous.
Why it happens
Primidone and its metabolite phenobarbital induce CYP3A4 and P-glycoprotein, increasing tacrolimus clearance.
What to do
Prefer a non-inducing anticonvulsant where possible. If the combination is needed, monitor tacrolimus troughs closely and increase the dose as required, with readjustment if primidone is stopped.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Tacrolimus
- Adenovirus types 4 and 7 live + Tacrolimus Contraindicated
- Bcg vaccine live + Tacrolimus Contraindicated
- Cidofovir + Tacrolimus Contraindicated
- Cyclosporin + Tacrolimus Contraindicated
- Influenza virus vaccine quadrivalent intranasal + Tacrolimus Contraindicated
- Measles mumps and rubella vaccine live + Tacrolimus Contraindicated
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 Primidone with Tacrolimus?
MediHelp rates the interaction as major. Primidone and Tacrolimus can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Primidone is metabolized to phenobarbital, a potent enzyme inducer that can substantially lower tacrolimus concentrations. This risks subtherapeutic immunosuppression and graft rejection in transplant recipients.
How serious is the interaction between Primidone and Tacrolimus?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Prefer a non-inducing anticonvulsant where possible. If the combination is needed, monitor tacrolimus troughs closely and increase the dose as required, with readjustment if primidone is stopped.
What other medicines interact with Tacrolimus?
MediHelp also lists interactions of Tacrolimus with, for example, Adenovirus types 4 and 7 live, Bcg vaccine live, Cidofovir. The full list is on the Tacrolimus page.
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