Drug interactions
Doxepin + Lithium
Severity: Moderate
Doxepin and Lithium: 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
Lithium combined with a tricyclic antidepressant such as doxepin may increase serotonergic effects and the risk of serotonin syndrome. Both drugs can also affect cardiac conduction and QT interval, and lithium toxicity can add neurotoxic effects. The combination is used in practice for mood disorders but needs surveillance.
What this interaction means in plain words
Doxepin and Lithium 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; Lithium belongs to Central Nervous System.
Why it happens
Additive serotonergic activity and additive effects on cardiac repolarization.
What to do
Monitor for signs of serotonin toxicity and tremor or confusion, and check serum lithium levels. Obtain an ECG at baseline and after dose changes, especially in patients with cardiac disease or electrolyte disturbance.
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 Lithium
- Lithium + Thioridazine Contraindicated
- Lithium + Vandetanib Contraindicated
- Aceclofenac + Lithium Major
- Acemetacin + Lithium Major
- Amisulpride + Lithium Major
- Amlodipine-benazepril + Lithium Major
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 Lithium?
MediHelp rates the interaction as moderate. Doxepin and Lithium 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. Lithium combined with a tricyclic antidepressant such as doxepin may increase serotonergic effects and the risk of serotonin syndrome. Both drugs can also affect cardiac conduction and QT interval, and lithium toxicity can add neurotoxic effects. The combination is used in practice for mood disorders but needs surveillance.
How serious is the interaction between Doxepin and Lithium?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for signs of serotonin toxicity and tremor or confusion, and check serum lithium levels. Obtain an ECG at baseline and after dose changes, especially in patients with cardiac disease or electrolyte disturbance.
What other medicines interact with Lithium?
MediHelp also lists interactions of Lithium with, for example, Thioridazine, Vandetanib, Aceclofenac. The full list is on the Lithium page.
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