Drug interactions
Phenobarbital + Quinine
Severity: Moderate
Phenobarbital and Quinine: 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 induces quinine metabolism and shortens its half-life, with lower plasma levels. Quinine may lose efficacy, and the effect can persist after phenobarbital is stopped.
What this interaction means in plain words
Phenobarbital and Quinine 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
Phenobarbital induces hepatic CYP3A4, increasing quinine clearance.
What to do
Monitor clinical response and quinine levels where available. Consider an alternative antimalarial or non-inducing anticonvulsant if feasible.
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 Quinine
- Arsenic trioxide + Quinine Contraindicated
- Dofetilide + Quinine Contraindicated
- Dronedarone + Quinine Contraindicated
- Ibutilide + Quinine Contraindicated
- Mefloquine + Quinine Contraindicated
- Nilotinib + Quinine Contraindicated
Frequently asked questions
Can I take Phenobarbital with Quinine?
MediHelp rates the interaction as moderate. Phenobarbital and Quinine 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 induces quinine metabolism and shortens its half-life, with lower plasma levels. Quinine may lose efficacy, and the effect can persist after phenobarbital is stopped.
How serious is the interaction between Phenobarbital and Quinine?
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 clinical response and quinine levels where available. Consider an alternative antimalarial or non-inducing anticonvulsant if feasible.
What other medicines interact with Quinine?
MediHelp also lists interactions of Quinine with, for example, Arsenic trioxide, Dofetilide, Dronedarone. The full list is on the Quinine page.
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