Drug interactions
Nortriptyline + Ritonavir
Severity: Major
Nortriptyline and Ritonavir: major 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
Ritonavir strongly inhibits CYP3A4 and also inhibits CYP2D6, which can raise nortriptyline concentrations. This increases the risk of anticholinergic effects, sedation, arrhythmia and QT prolongation.
What this interaction means in plain words
Nortriptyline 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.
Nortriptyline belongs to Central Nervous System; Ritonavir belongs to Anti Virals.
Why it happens
Ritonavir inhibition of CYP2D6 and CYP3A4 reduces nortriptyline metabolism.
What to do
Start nortriptyline at a lower dose and titrate to response. Monitor ECG and nortriptyline plasma levels, and watch for anticholinergic 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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Other interactions of Nortriptyline
- Disopyramide + Nortriptyline Contraindicated
- Dofetilide + Nortriptyline Contraindicated
- Dronedarone + Nortriptyline Contraindicated
- Ibutilide + Nortriptyline Contraindicated
- Isocarboxazid + Nortriptyline Contraindicated
- Methylene blue + Nortriptyline 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 Nortriptyline with Ritonavir?
MediHelp rates the interaction as major. Nortriptyline 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 strongly inhibits CYP3A4 and also inhibits CYP2D6, which can raise nortriptyline concentrations. This increases the risk of anticholinergic effects, sedation, arrhythmia and QT prolongation.
How serious is the interaction between Nortriptyline 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 nortriptyline at a lower dose and titrate to response. Monitor ECG and nortriptyline plasma levels, and watch for anticholinergic toxicity.
What other medicines interact with Nortriptyline?
MediHelp also lists interactions of Nortriptyline with, for example, Disopyramide, Dofetilide, Dronedarone. The full list is on the Nortriptyline page.
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