Drug interactions
Clozapine + Fluphenazine
Severity: Major
Clozapine and Fluphenazine: 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 two antipsychotics increases sedation, anticholinergic effects, extrapyramidal symptoms, the risk of neuroleptic malignant syndrome and QTc prolongation. Clozapine also carries risks of seizures, myocarditis, orthostatic hypotension and respiratory depression that may be amplified by CNS depressants.
What this interaction means in plain words
Clozapine and Fluphenazine 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; Fluphenazine belongs to Central Nervous System.
Why it happens
Additive dopamine receptor blockade, CNS depression, anticholinergic effects and effects on cardiac repolarization.
What to do
Use the combination only when clearly indicated, with close monitoring of sedation, blood pressure, ECG and electrolytes and for signs of neuroleptic malignant syndrome. Use the lowest effective doses.
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 Fluphenazine
- Arsenic trioxide + Fluphenazine Contraindicated
- Dofetilide + Fluphenazine Contraindicated
- Fluphenazine + Ibutilide Contraindicated
- Fluphenazine + Pimozide Contraindicated
- Adagrasib + Fluphenazine Major
- Alfentanil + Fluphenazine Major
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 Fluphenazine?
MediHelp rates the interaction as major. Clozapine and Fluphenazine 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 two antipsychotics increases sedation, anticholinergic effects, extrapyramidal symptoms, the risk of neuroleptic malignant syndrome and QTc prolongation. Clozapine also carries risks of seizures, myocarditis, orthostatic hypotension and respiratory depression that may be amplified by CNS depressants.
How serious is the interaction between Clozapine and Fluphenazine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use the combination only when clearly indicated, with close monitoring of sedation, blood pressure, ECG and electrolytes and for signs of neuroleptic malignant syndrome. Use the lowest effective doses.
What other medicines interact with Fluphenazine?
MediHelp also lists interactions of Fluphenazine with, for example, Arsenic trioxide, Dofetilide, Ibutilide. The full list is on the Fluphenazine page.
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