Drug interactions
Doxepin + Loperamide
Severity: Moderate
Doxepin and Loperamide: 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
Doxepin, a tricyclic antidepressant, can prolong the QT interval, and loperamide does so at high doses. Combined use may raise arrhythmia risk, and both drugs can slow gut motility through anticholinergic or opioid effects.
What this interaction means in plain words
Doxepin and Loperamide 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; Loperamide belongs to Gastrointestinal Tract.
Why it happens
Additive QT prolongation, plus additive reduction in gastrointestinal motility.
What to do
Keep loperamide within labeled doses and monitor for constipation and palpitations. Obtain an ECG in patients with cardiac disease or other QT-prolonging drugs.
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 Loperamide
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 Loperamide?
MediHelp rates the interaction as moderate. Doxepin and Loperamide 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, a tricyclic antidepressant, can prolong the QT interval, and loperamide does so at high doses. Combined use may raise arrhythmia risk, and both drugs can slow gut motility through anticholinergic or opioid effects.
How serious is the interaction between Doxepin and Loperamide?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Keep loperamide within labeled doses and monitor for constipation and palpitations. Obtain an ECG in patients with cardiac disease or other QT-prolonging drugs.
What other medicines interact with Loperamide?
MediHelp also lists interactions of Loperamide with, for example, Amiodarone, Amisulpride, Anagrelide. The full list is on the Loperamide page.
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