Drug interactions
Doxepin + Quinine
Severity: Moderate
Doxepin and Quinine: 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 can prolong the QT interval, so the combination increases the risk of arrhythmia including torsades de pointes. Risk is higher at higher doses of doxepin and with electrolyte imbalance.
What this interaction means in plain words
Doxepin and Quinine 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; Quinine belongs to Anti Parasitic.
Why it happens
Additive QT prolongation through cardiac ion channel blockade.
What to do
Obtain an ECG and correct potassium and magnesium before co-use. Monitor the QTc and keep doxepin doses low.
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 Quinine
- Arsenic trioxide + Quinine Contraindicated
- Dofetilide + Quinine Contraindicated
- Dronedarone + Quinine Contraindicated
- Ibutilide + Quinine Contraindicated
- Mefloquine + Quinine Contraindicated
- Nilotinib + Quinine 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 Quinine?
MediHelp rates the interaction as moderate. Doxepin and Quinine 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 can prolong the QT interval, so the combination increases the risk of arrhythmia including torsades de pointes. Risk is higher at higher doses of doxepin and with electrolyte imbalance.
How serious is the interaction between Doxepin and Quinine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain an ECG and correct potassium and magnesium before co-use. Monitor the QTc and keep doxepin doses low.
What other medicines interact with Quinine?
MediHelp also lists interactions of Quinine with, for example, Arsenic trioxide, Dofetilide, Dronedarone. The full list is on the Quinine page.
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