Drug interactions
Doxepin + Olanzapine
Severity: Moderate
Doxepin and Olanzapine: moderate 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 cause sedation, anticholinergic effects and orthostatic hypotension, and each can modestly prolong the QT interval. The combination can therefore increase drowsiness, confusion and, rarely, arrhythmia risk.
What this interaction means in plain words
Doxepin and Olanzapine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Doxepin belongs to Dermatology; Olanzapine belongs to Central Nervous System.
Why it happens
Additive CNS depression, anticholinergic and hypotensive effects, and additive QT prolongation.
What to do
Use the lowest effective doses and monitor sedation, orthostatic blood pressure and anticholinergic effects. Obtain an ECG if other QT risk factors are present.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Olanzapine
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 Olanzapine?
MediHelp rates the interaction as moderate. Doxepin and Olanzapine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Both drugs cause sedation, anticholinergic effects and orthostatic hypotension, and each can modestly prolong the QT interval. The combination can therefore increase drowsiness, confusion and, rarely, arrhythmia risk.
How serious is the interaction between Doxepin and Olanzapine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use the lowest effective doses and monitor sedation, orthostatic blood pressure and anticholinergic effects. Obtain an ECG if other QT risk factors are present.
What other medicines interact with Olanzapine?
MediHelp also lists interactions of Olanzapine with, for example, Amisulpride, Amoxapine, Apomorphine. The full list is on the Olanzapine page.
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