Drug interactions
Amitriptyline + Ritonavir
Severity: Major
Amitriptyline and Ritonavir: major interaction.
Last updated Sources: US FDA label
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
Ritonavir inhibits the metabolism of amitriptyline and can raise tricyclic concentrations. This increases the risk of anticholinergic effects, sedation, hypotension, and cardiac conduction abnormalities including QT prolongation.
What this interaction means in plain words
Amitriptyline and Ritonavir can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Amitriptyline belongs to Central Nervous System; Ritonavir belongs to Anti Virals.
Why it happens
Ritonavir inhibits CYP3A4 and CYP2D6 (and P-glycoprotein), reducing amitriptyline clearance.
What to do
Start with a lower amitriptyline dose and titrate according to response and tolerability. Monitor ECG and tricyclic levels where available, and watch for toxicity.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Amitriptyline
- Amitriptyline + Isocarboxazid Contraindicated
- Amitriptyline + Methylene blue Contraindicated
- Amitriptyline + Phenelzine Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amitriptyline + Procarbazine Contraindicated
- Amitriptyline + Safinamide Contraindicated
Other interactions of Ritonavir
- Alfuzosin + Ritonavir Contraindicated
- Amiodarone + Ritonavir Contraindicated
- Avanafil + Ritonavir Contraindicated
- Colchicine + Ritonavir Contraindicated
- Dronedarone + Ritonavir Contraindicated
- Eletriptan + Ritonavir Contraindicated
Frequently asked questions
Can I take Amitriptyline with Ritonavir?
MediHelp rates the interaction as major. Amitriptyline and Ritonavir can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Ritonavir inhibits the metabolism of amitriptyline and can raise tricyclic concentrations. This increases the risk of anticholinergic effects, sedation, hypotension, and cardiac conduction abnormalities including QT prolongation.
How serious is the interaction between Amitriptyline and Ritonavir?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Start with a lower amitriptyline dose and titrate according to response and tolerability. Monitor ECG and tricyclic levels where available, and watch for toxicity.
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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