Drug interactions
Phenytoin + Tibolone
Severity: Minor
Phenytoin and Tibolone: minor 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
Enzyme-inducing antiepileptics such as phenytoin may speed the metabolism of tibolone and lower its active metabolites. This could reduce relief of menopausal symptoms.
What this interaction means in plain words
Phenytoin and Tibolone have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Phenytoin belongs to Central Nervous System; Tibolone belongs to Endocrine.
Why it happens
Phenytoin induces hepatic enzymes (including CYP3A4) that metabolize tibolone.
What to do
Monitor for loss of symptom control or breakthrough bleeding. Adjust the tibolone dose or consider alternatives if the response is inadequate.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Phenytoin
- Artemether / lumefantrine + Phenytoin Contraindicated
- Bictegravir + Phenytoin Contraindicated
- Cabotegravir + Phenytoin Contraindicated
- Doravirine + Phenytoin Contraindicated
- Elbasvir / grazoprevir + Phenytoin Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Phenytoin Contraindicated
Other interactions of Tibolone
- Amobarbital + Tibolone Moderate
- Carbamazepine + Tibolone Moderate
- Secobarbital + Tibolone Moderate
- Alogliptin-metformin + Tibolone Minor
- Argatroban + Tibolone Minor
- Dapagliflozin-metformin + Tibolone Minor
Frequently asked questions
Can I take Phenytoin with Tibolone?
MediHelp rates the interaction as minor. Phenytoin and Tibolone have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Enzyme-inducing antiepileptics such as phenytoin may speed the metabolism of tibolone and lower its active metabolites. This could reduce relief of menopausal symptoms.
How serious is the interaction between Phenytoin and Tibolone?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for loss of symptom control or breakthrough bleeding. Adjust the tibolone dose or consider alternatives if the response is inadequate.
What other medicines interact with Phenytoin?
MediHelp also lists interactions of Phenytoin with, for example, Artemether / lumefantrine, Bictegravir, Cabotegravir. The full list is on the Phenytoin page.
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