Drug interactions
Conivaptan + Simvastatin
Severity: Major
Conivaptan and Simvastatin: 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
Conivaptan is a strong CYP3A4 inhibitor and may increase simvastatin exposure, raising the risk of myopathy and rhabdomyolysis. Use is generally avoided.
What this interaction means in plain words
Conivaptan and Simvastatin 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
Conivaptan inhibits CYP3A4, reducing the metabolism of simvastatin.
What to do
Hold simvastatin during the short conivaptan infusion, or use a non-CYP3A4 statin, and watch for muscle pain or raised CK.
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 Simvastatin
- Atazanavir + Simvastatin Contraindicated
- Clarithromycin + Simvastatin Contraindicated
- Cobicistat + Simvastatin Contraindicated
- Cyclosporin + Simvastatin Contraindicated
- Danazol + Simvastatin Contraindicated
- Darunavir + Simvastatin Contraindicated
Frequently asked questions
Can I take Conivaptan with Simvastatin?
MediHelp rates the interaction as major. Conivaptan and Simvastatin 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. Conivaptan is a strong CYP3A4 inhibitor and may increase simvastatin exposure, raising the risk of myopathy and rhabdomyolysis. Use is generally avoided.
How serious is the interaction between Conivaptan and Simvastatin?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Hold simvastatin during the short conivaptan infusion, or use a non-CYP3A4 statin, and watch for muscle pain or raised CK.
What other medicines interact with Simvastatin?
MediHelp also lists interactions of Simvastatin with, for example, Atazanavir, Clarithromycin, Cobicistat. The full list is on the Simvastatin page.
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