Drug interactions
Protriptyline + Risperidone
Severity: Major
Protriptyline and Risperidone: major interaction.
Last updated Sources: UK SmPC
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
Both drugs can prolong the QTc interval, raising the risk of torsades de pointes, especially with other risk factors. Additive sedation, orthostatic hypotension and anticholinergic effects may also occur. Protriptyline may also modestly raise risperidone levels via CYP2D6 inhibition.
What this interaction means in plain words
Protriptyline and Risperidone 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.
Why it happens
Additive QT prolongation and CNS depression, with possible CYP2D6 inhibition.
What to do
Obtain a baseline ECG and monitor QTc, and correct potassium and magnesium. Avoid the combination in patients with QT risk factors and consider a lower risperidone dose.
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 Risperidone
- Ibutilide + Risperidone Contraindicated
- Risperidone + Vandetanib Contraindicated
- Adagrasib + Risperidone Major
- Amiodarone + Risperidone Major
- Amisulpride + Risperidone Major
- Amoxapine + Risperidone Major
Frequently asked questions
Can I take Protriptyline with Risperidone?
MediHelp rates the interaction as major. Protriptyline and Risperidone 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. Both drugs can prolong the QTc interval, raising the risk of torsades de pointes, especially with other risk factors. Additive sedation, orthostatic hypotension and anticholinergic effects may also occur. Protriptyline may also modestly raise risperidone levels via CYP2D6 inhibition.
How serious is the interaction between Protriptyline and Risperidone?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain a baseline ECG and monitor QTc, and correct potassium and magnesium. Avoid the combination in patients with QT risk factors and consider a lower risperidone dose.
What other medicines interact with Risperidone?
MediHelp also lists interactions of Risperidone with, for example, Ibutilide, Vandetanib, Adagrasib. The full list is on the Risperidone page.
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