Drug interactions
Amitriptyline + Rifampin
Severity: Moderate
Amitriptyline and Rifampin: 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
Rifampin induces the enzymes that clear amitriptyline and its active metabolite nortriptyline, which lowers their plasma concentrations. This can lead to loss of antidepressant or analgesic effect, and withdrawal-like symptoms may occur if induction is marked.
What this interaction means in plain words
Amitriptyline and Rifampin 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.
Why it happens
Rifampin induces CYP3A4 and CYP2C19 (and possibly P-glycoprotein), increasing the metabolism and clearance of amitriptyline.
What to do
Monitor clinical response and, where available, tricyclic serum levels, and increase the amitriptyline dose if needed. Reassess the dose after rifampin is stopped, as levels will rise again over a few weeks.
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 Amitriptyline
- Amitriptyline + Isocarboxazid Contraindicated
- Amitriptyline + Methylene blue Contraindicated
- Amitriptyline + Phenelzine Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amitriptyline + Procarbazine Contraindicated
- Amitriptyline + Safinamide Contraindicated
Frequently asked questions
Can I take Amitriptyline with Rifampin?
MediHelp rates the interaction as moderate. Amitriptyline and Rifampin 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. Rifampin induces the enzymes that clear amitriptyline and its active metabolite nortriptyline, which lowers their plasma concentrations. This can lead to loss of antidepressant or analgesic effect, and withdrawal-like symptoms may occur if induction is marked.
How serious is the interaction between Amitriptyline and Rifampin?
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 clinical response and, where available, tricyclic serum levels, and increase the amitriptyline dose if needed. Reassess the dose after rifampin is stopped, as levels will rise again over a few weeks.
What other medicines interact with Amitriptyline?
MediHelp also lists interactions of Amitriptyline with, for example, Isocarboxazid, Methylene blue, Phenelzine. The full list is on the Amitriptyline page.
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