Drug interactions
Amitriptyline + Ketoconazole
Severity: Major
Amitriptyline 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 agents can prolong the QT interval, so combined use raises the risk of ventricular arrhythmia including torsades de pointes. Ketoconazole may also increase tricyclic levels by inhibiting its metabolism.
What this interaction means in plain words
Amitriptyline 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.
Amitriptyline belongs to Central Nervous System; Ketoconazole belongs to Anti Fungals.
Why it happens
Additive QT prolongation, with possible CYP3A4 and CYP2C19 inhibition raising amitriptyline exposure.
What to do
Avoid concurrent use if possible, or choose an alternative antifungal. If co-administered, check baseline and follow-up ECG, correct electrolytes and consider a lower tricyclic dose.
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 Amitriptyline
- Amitriptyline + Isocarboxazid Contraindicated
- Amitriptyline + Methylene blue Contraindicated
- Amitriptyline + Phenelzine Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amitriptyline + Procarbazine Contraindicated
- Amitriptyline + Safinamide Contraindicated
Frequently asked questions
Can I take Amitriptyline with Ketoconazole?
MediHelp rates the interaction as major. Amitriptyline 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 agents can prolong the QT interval, so combined use raises the risk of ventricular arrhythmia including torsades de pointes. Ketoconazole may also increase tricyclic levels by inhibiting its metabolism.
How serious is the interaction between Amitriptyline 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 concurrent use if possible, or choose an alternative antifungal. If co-administered, check baseline and follow-up ECG, correct electrolytes and consider a lower tricyclic dose.
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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