Drug interactions
Phenobarbital + Solifenacin
Severity: Moderate
Phenobarbital and Solifenacin: 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
Phenobarbital is a CYP3A4 inducer and can reduce solifenacin exposure, leading to loss of symptom control. Induction develops over days to weeks and fades slowly after stopping.
What this interaction means in plain words
Phenobarbital and Solifenacin 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.
Why it happens
Induction of CYP3A4 by phenobarbital increases solifenacin metabolism.
What to do
Monitor therapeutic response and titrate solifenacin to effect within labeled limits, or use an alternative; reassess the dose if phenobarbital is discontinued.
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 Solifenacin
Frequently asked questions
Can I take Phenobarbital with Solifenacin?
MediHelp rates the interaction as moderate. Phenobarbital and Solifenacin 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. Phenobarbital is a CYP3A4 inducer and can reduce solifenacin exposure, leading to loss of symptom control. Induction develops over days to weeks and fades slowly after stopping.
How serious is the interaction between Phenobarbital and Solifenacin?
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 therapeutic response and titrate solifenacin to effect within labeled limits, or use an alternative; reassess the dose if phenobarbital is discontinued.
What other medicines interact with Solifenacin?
MediHelp also lists interactions of Solifenacin with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Solifenacin page.
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