Drug interactions
Fluphenazine + Ketoconazole
Severity: Major
Fluphenazine and Ketoconazole: 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
Both drugs can prolong the QT interval, so combined use increases the risk of ventricular arrhythmias including torsades de pointes.
What this interaction means in plain words
Fluphenazine and Ketoconazole 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.
Fluphenazine belongs to Central Nervous System; Ketoconazole belongs to Anti Fungals.
Why it happens
Additive QT interval prolongation.
What to do
Avoid the combination if possible. If necessary, obtain baseline and follow-up ECGs and keep potassium and magnesium within normal range.
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 Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole Contraindicated
Other interactions of Fluphenazine
- Arsenic trioxide + Fluphenazine Contraindicated
- Dofetilide + Fluphenazine Contraindicated
- Fluphenazine + Ibutilide Contraindicated
- Fluphenazine + Pimozide Contraindicated
- Adagrasib + Fluphenazine Major
- Alfentanil + Fluphenazine Major
Frequently asked questions
Can I take Fluphenazine with Ketoconazole?
MediHelp rates the interaction as major. Fluphenazine and Ketoconazole 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. Both drugs can prolong the QT interval, so combined use increases the risk of ventricular arrhythmias including torsades de pointes.
How serious is the interaction between Fluphenazine and Ketoconazole?
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 if possible. If necessary, obtain baseline and follow-up ECGs and keep potassium and magnesium within normal range.
What other medicines interact with Ketoconazole?
MediHelp also lists interactions of Ketoconazole with, for example, Alfuzosin, Alprazolam, Avanafil. The full list is on the Ketoconazole page.
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