Drug interactions
Griseofulvin + Phenobarbital
Severity: Moderate
Griseofulvin and Phenobarbital: 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 can reduce griseofulvin blood concentrations and may lead to therapeutic failure in dermatophyte infections. This has been described in labeling and case reports.
What this interaction means in plain words
Griseofulvin and Phenobarbital 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 reduces griseofulvin absorption and induces hepatic enzymes that increase its clearance.
What to do
Monitor clinical response and consider a higher griseofulvin dose if the combination is unavoidable; an alternative antifungal may be preferable.
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 Griseofulvin
Frequently asked questions
Can I take Griseofulvin with Phenobarbital?
MediHelp rates the interaction as moderate. Griseofulvin and Phenobarbital 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 can reduce griseofulvin blood concentrations and may lead to therapeutic failure in dermatophyte infections. This has been described in labeling and case reports.
How serious is the interaction between Griseofulvin and Phenobarbital?
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 consider a higher griseofulvin dose if the combination is unavoidable; an alternative antifungal may be preferable.
What other medicines interact with Griseofulvin?
MediHelp also lists interactions of Griseofulvin with, for example, Cyclosporine, Cyclosporin, Desogestrel-ethinyl estradiol. The full list is on the Griseofulvin page.
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