Drug interactions
Griseofulvin + Ulipristal
Severity: Major
Griseofulvin and Ulipristal: 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
Griseofulvin is a CYP3A4 inducer and may lower ulipristal exposure. This can reduce the efficacy of ulipristal as emergency contraception, and the effect may persist for weeks after griseofulvin is stopped.
What this interaction means in plain words
Griseofulvin and Ulipristal 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 griseofulvin increases the metabolism of ulipristal.
What to do
Avoid ulipristal in patients taking or recently treated with griseofulvin and use a copper intrauterine device or another non-hormonal emergency method instead. Advise reliable non-hormonal contraception during and for some weeks after griseofulvin.
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 Griseofulvin
Frequently asked questions
Can I take Griseofulvin with Ulipristal?
MediHelp rates the interaction as major. Griseofulvin and Ulipristal 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. Griseofulvin is a CYP3A4 inducer and may lower ulipristal exposure. This can reduce the efficacy of ulipristal as emergency contraception, and the effect may persist for weeks after griseofulvin is stopped.
How serious is the interaction between Griseofulvin and Ulipristal?
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 ulipristal in patients taking or recently treated with griseofulvin and use a copper intrauterine device or another non-hormonal emergency method instead. Advise reliable non-hormonal contraception during and for some weeks after griseofulvin.
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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