Drug interactions
Clozapine + Diazepam
Severity: Major
Clozapine and Diazepam: 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
Combining a benzodiazepine with clozapine can cause marked sedation, hypotension and in rare cases respiratory or cardiovascular collapse, particularly during clozapine initiation or dose escalation. Reports describe this risk even though many patients use the combination safely.
What this interaction means in plain words
Clozapine and Diazepam 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.
Clozapine belongs to Central Nervous System; Diazepam belongs to Musculoskeletal.
Why it happens
Additive CNS and respiratory depression and hypotension through GABA-A potentiation and clozapine's multi-receptor antagonism.
What to do
Avoid starting or rapidly increasing both drugs together, and use the lowest effective benzodiazepine dose. Monitor blood pressure, respiration and sedation closely, especially in the first weeks.
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 Diazepam
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 Diazepam?
MediHelp rates the interaction as major. Clozapine and Diazepam 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 a benzodiazepine with clozapine can cause marked sedation, hypotension and in rare cases respiratory or cardiovascular collapse, particularly during clozapine initiation or dose escalation. Reports describe this risk even though many patients use the combination safely.
How serious is the interaction between Clozapine and Diazepam?
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 or rapidly increasing both drugs together, and use the lowest effective benzodiazepine dose. Monitor blood pressure, respiration and sedation closely, especially in the first weeks.
What other medicines interact with Diazepam?
MediHelp also lists interactions of Diazepam with, for example, Calcium / magnesium / potassium / sodium oxybates, Alfentanil, Alprazolam. The full list is on the Diazepam page.
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