Drug interactions
Ketoconazole + Tolvaptan
Severity: Contraindicated
Ketoconazole and Tolvaptan: contraindicated 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
Ketoconazole greatly increases tolvaptan exposure. This can cause excessively rapid aquaresis, dehydration, hypernatremia and osmotic demyelination risk from overly fast sodium correction.
What this interaction means in plain words
Ketoconazole and Tolvaptan are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Ketoconazole belongs to Anti Fungals; Tolvaptan belongs to Endocrine.
Why it happens
Strong CYP3A4 inhibition markedly decreases tolvaptan metabolism.
What to do
Avoid the combination; strong CYP3A4 inhibitors are contraindicated with tolvaptan. Use an alternative antifungal, or hold tolvaptan during treatment.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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Other interactions of Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole Contraindicated
Other interactions of Tolvaptan
- Atazanavir + Tolvaptan Contraindicated
- Ceritinib + Tolvaptan Contraindicated
- Cobicistat + Tolvaptan Contraindicated
- Conivaptan + Tolvaptan Contraindicated
- Darunavir + Tolvaptan Contraindicated
- Idelalisib + Tolvaptan Contraindicated
Frequently asked questions
Can I take Ketoconazole with Tolvaptan?
MediHelp rates the interaction as contraindicated. Ketoconazole and Tolvaptan are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Ketoconazole greatly increases tolvaptan exposure. This can cause excessively rapid aquaresis, dehydration, hypernatremia and osmotic demyelination risk from overly fast sodium correction.
How serious is the interaction between Ketoconazole and Tolvaptan?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination; strong CYP3A4 inhibitors are contraindicated with tolvaptan. Use an alternative antifungal, or hold tolvaptan during treatment.
What other medicines interact with Ketoconazole?
MediHelp also lists interactions of Ketoconazole with, for example, Alfuzosin, Alprazolam, Avanafil. The full list is on the Ketoconazole page.
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