Drug interactions
Doxepin + Ziprasidone
Severity: Major
Doxepin and Ziprasidone: 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
Doxepin, a tricyclic antidepressant, can prolong the QT interval and slow cardiac conduction, particularly at higher doses or in overdose. Together with ziprasidone, the risk of QTc prolongation and ventricular arrhythmia is increased.
What this interaction means in plain words
Doxepin and Ziprasidone 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.
Doxepin belongs to Dermatology; Ziprasidone belongs to Central Nervous System.
Why it happens
Additive inhibition of cardiac repolarizing potassium currents, producing additive QT prolongation.
What to do
Avoid the combination where possible and use an alternative with less QT effect. If it is unavoidable, obtain a baseline ECG, correct potassium and magnesium, and repeat ECG monitoring.
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 Ziprasidone
- Amiodarone + Ziprasidone Contraindicated
- Amitriptyline + Ziprasidone Contraindicated
- Arsenic trioxide + Ziprasidone Contraindicated
- Bedaquiline + Ziprasidone Contraindicated
- Chloroquine + Ziprasidone Contraindicated
- Citalopram + Ziprasidone Contraindicated
Other interactions of Doxepin
- Doxepin + Isocarboxazid Contraindicated
- Doxepin + Phenelzine Contraindicated
- Doxepin + Procarbazine Contraindicated
- Doxepin + Safinamide Contraindicated
- Doxepin + Selegiline Contraindicated
- Doxepin + Tranylcypromine Contraindicated
Frequently asked questions
Can I take Doxepin with Ziprasidone?
MediHelp rates the interaction as major. Doxepin and Ziprasidone 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. Doxepin, a tricyclic antidepressant, can prolong the QT interval and slow cardiac conduction, particularly at higher doses or in overdose. Together with ziprasidone, the risk of QTc prolongation and ventricular arrhythmia is increased.
How serious is the interaction between Doxepin and Ziprasidone?
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 where possible and use an alternative with less QT effect. If it is unavoidable, obtain a baseline ECG, correct potassium and magnesium, and repeat ECG monitoring.
What other medicines interact with Ziprasidone?
MediHelp also lists interactions of Ziprasidone with, for example, Amiodarone, Amitriptyline, Arsenic trioxide. The full list is on the Ziprasidone page.
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