Drug interactions
Posaconazole + Primidone
Severity: Major
Posaconazole and Primidone: major interaction.
Last updated Sources: US FDA label
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, which is partly converted to phenobarbital, can reduce posaconazole concentrations and risk breakthrough fungal infection.
What this interaction means in plain words
Posaconazole and Primidone 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.
Posaconazole belongs to Anti Fungals; Primidone belongs to Central Nervous System.
Why it happens
Primidone and its phenobarbital metabolite induce UDP-glucuronosyltransferase and efflux transporters, increasing posaconazole clearance.
What to do
Avoid the combination if possible; otherwise monitor posaconazole trough concentrations and clinical response and adjust the dose accordingly.
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 Posaconazole
- Artemether + Posaconazole Contraindicated
- Avanafil + Posaconazole Contraindicated
- Cobimetinib + Posaconazole Contraindicated
- Conivaptan + Posaconazole Contraindicated
- Dihydroergotamine intranasal + Posaconazole Contraindicated
- Dihydroergotamine + Posaconazole 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 Posaconazole with Primidone?
MediHelp rates the interaction as major. Posaconazole and Primidone 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, which is partly converted to phenobarbital, can reduce posaconazole concentrations and risk breakthrough fungal infection.
How serious is the interaction between Posaconazole and Primidone?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination if possible; otherwise monitor posaconazole trough concentrations and clinical response and adjust the dose accordingly.
What other medicines interact with Posaconazole?
MediHelp also lists interactions of Posaconazole with, for example, Artemether, Avanafil, Cobimetinib. The full list is on the Posaconazole page.
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