Drug interactions
Clozapine + Flurazepam
Severity: Major
Clozapine and Flurazepam: 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
Combining clozapine with a benzodiazepine increases sedation and may cause respiratory depression, hypotension and syncope; rare collapse has been reported. Flurazepam's long-acting active metabolite prolongs the exposure, raising the risk of next-day impairment and falls.
What this interaction means in plain words
Clozapine and Flurazepam 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
Additive CNS depression and hypotension through GABA-A potentiation and clozapine's receptor antagonism.
What to do
Avoid starting both together and use the lowest effective flurazepam dose, or choose a shorter-acting hypnotic. Monitor sedation, respiratory status and blood pressure, especially in older patients.
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 Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Frequently asked questions
Can I take Clozapine with Flurazepam?
MediHelp rates the interaction as major. Clozapine and Flurazepam 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. Combining clozapine with a benzodiazepine increases sedation and may cause respiratory depression, hypotension and syncope; rare collapse has been reported. Flurazepam's long-acting active metabolite prolongs the exposure, raising the risk of next-day impairment and falls.
How serious is the interaction between Clozapine and Flurazepam?
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 starting both together and use the lowest effective flurazepam dose, or choose a shorter-acting hypnotic. Monitor sedation, respiratory status and blood pressure, especially in older patients.
What other medicines interact with Clozapine?
MediHelp also lists interactions of Clozapine with, for example, Deferiprone, Irinotecan, Pimozide. The full list is on the Clozapine page.
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