Drug interactions
Nelfinavir + Tolvaptan
Severity: Major
Nelfinavir and Tolvaptan: major 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
Nelfinavir is a CYP3A4 inhibitor and can markedly raise tolvaptan exposure. Excess tolvaptan can cause overly rapid aquaresis, dehydration, hypernatremia and rapid sodium correction with a risk of osmotic demyelination.
What this interaction means in plain words
Nelfinavir 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.
Nelfinavir belongs to Anti Virals; Tolvaptan belongs to Endocrine.
Why it happens
Inhibition of CYP3A4-mediated metabolism of tolvaptan reduces its clearance.
What to do
Avoid the combination where possible and choose an alternative to nelfinavir or tolvaptan. If used, monitor serum sodium and volume status closely and consider a lower tolvaptan dose per labeling.
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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Other interactions of Tolvaptan
- Atazanavir + Tolvaptan Contraindicated
- Ceritinib + Tolvaptan Contraindicated
- Cobicistat + Tolvaptan Contraindicated
- Conivaptan + Tolvaptan Contraindicated
- Darunavir + Tolvaptan Contraindicated
- Idelalisib + Tolvaptan Contraindicated
Other interactions of Nelfinavir
- Alfuzosin + Nelfinavir Contraindicated
- Avanafil + Nelfinavir Contraindicated
- Dronedarone + Nelfinavir Contraindicated
- Eletriptan + Nelfinavir Contraindicated
- Ergotamine + Nelfinavir Contraindicated
- Flibanserin + Nelfinavir Contraindicated
Frequently asked questions
Can I take Nelfinavir with Tolvaptan?
MediHelp rates the interaction as major. Nelfinavir 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. Nelfinavir is a CYP3A4 inhibitor and can markedly raise tolvaptan exposure. Excess tolvaptan can cause overly rapid aquaresis, dehydration, hypernatremia and rapid sodium correction with a risk of osmotic demyelination.
How serious is the interaction between Nelfinavir 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 the combination where possible and choose an alternative to nelfinavir or tolvaptan. If used, monitor serum sodium and volume status closely and consider a lower tolvaptan dose per labeling.
What other medicines interact with Tolvaptan?
MediHelp also lists interactions of Tolvaptan with, for example, Atazanavir, Ceritinib, Cobicistat. The full list is on the Tolvaptan page.
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