Drug interactions
Butabarbital + Tolvaptan
Severity: Major
Butabarbital and Tolvaptan: major interaction.
Last updated Sources: EMA 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
Barbiturates induce CYP3A4 and can lower tolvaptan concentrations. Reduced exposure may lead to loss of the aquaretic and sodium-raising effect.
What this interaction means in plain words
Butabarbital and Tolvaptan 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.
Why it happens
Induction of CYP3A4 by the barbiturate increases tolvaptan metabolism.
What to do
Avoid the combination if possible and choose a non-inducing sedative. If used together, monitor serum sodium and clinical response and adjust the tolvaptan dose as needed.
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 Tolvaptan
- Atazanavir + Tolvaptan Contraindicated
- Ceritinib + Tolvaptan Contraindicated
- Cobicistat + Tolvaptan Contraindicated
- Conivaptan + Tolvaptan Contraindicated
- Darunavir + Tolvaptan Contraindicated
- Idelalisib + Tolvaptan Contraindicated
Frequently asked questions
Can I take Butabarbital with Tolvaptan?
MediHelp rates the interaction as major. Butabarbital and Tolvaptan 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. Barbiturates induce CYP3A4 and can lower tolvaptan concentrations. Reduced exposure may lead to loss of the aquaretic and sodium-raising effect.
How serious is the interaction between Butabarbital and Tolvaptan?
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 and choose a non-inducing sedative. If used together, monitor serum sodium and clinical response and adjust the tolvaptan dose as needed.
What other medicines interact with Tolvaptan?
MediHelp also lists interactions of Tolvaptan with, for example, Atazanavir, Ceritinib, Cobicistat. The full list is on the Tolvaptan page.
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