Drug interactions
Carbamazepine + Tolvaptan
Severity: Major
Carbamazepine and Tolvaptan: major interaction.
Last updated Sources: UK SmPC
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
Carbamazepine can markedly decrease tolvaptan concentrations, which may lead to loss of aquaretic effect and inadequate treatment of hyponatremia.
What this interaction means in plain words
Carbamazepine and Tolvaptan 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.
Carbamazepine belongs to Central Nervous System; Tolvaptan belongs to Endocrine.
Why it happens
Induction of CYP3A4-mediated tolvaptan metabolism.
What to do
Avoid coadministration and choose a non-inducing anticonvulsant. If unavoidable, monitor serum sodium and clinical response closely.
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 Carbamazepine
- Artemether / lumefantrine + Carbamazepine Contraindicated
- Cabotegravir + Carbamazepine Contraindicated
- Carbamazepine + Delamanid Contraindicated
- Carbamazepine + Dienogest / estradiol valerate Contraindicated
- Carbamazepine + Doravirine Contraindicated
- Carbamazepine + Elbasvir / grazoprevir 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 Carbamazepine with Tolvaptan?
MediHelp rates the interaction as major. Carbamazepine and Tolvaptan 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. Carbamazepine can markedly decrease tolvaptan concentrations, which may lead to loss of aquaretic effect and inadequate treatment of hyponatremia.
How serious is the interaction between Carbamazepine and Tolvaptan?
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 coadministration and choose a non-inducing anticonvulsant. If unavoidable, monitor serum sodium and clinical response closely.
What other medicines interact with Carbamazepine?
MediHelp also lists interactions of Carbamazepine with, for example, Artemether / lumefantrine, Cabotegravir, Delamanid. The full list is on the Carbamazepine page.
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