Drug interactions
Lorcaserin + Thioridazine
Severity: Major
Lorcaserin and Thioridazine: 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
Lorcaserin inhibits CYP2D6, which is the main enzyme metabolizing thioridazine, and could raise thioridazine levels. Higher thioridazine exposure increases the risk of QT prolongation and arrhythmias, and lorcaserin also has serotonergic effects.
What this interaction means in plain words
Lorcaserin and Thioridazine 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
Inhibition of CYP2D6 by lorcaserin reduces thioridazine metabolism.
What to do
Avoid the combination where possible; if used, monitor ECG and for signs of thioridazine toxicity and consider reducing the thioridazine 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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Other interactions of Thioridazine
- Abiraterone + Thioridazine Contraindicated
- Adagrasib + Thioridazine Contraindicated
- Amiodarone + Thioridazine Contraindicated
- Amisulpride + Thioridazine Contraindicated
- Amitriptyline + Thioridazine Contraindicated
- Amoxapine + Thioridazine Contraindicated
Frequently asked questions
Can I take Lorcaserin with Thioridazine?
MediHelp rates the interaction as major. Lorcaserin and Thioridazine 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. Lorcaserin inhibits CYP2D6, which is the main enzyme metabolizing thioridazine, and could raise thioridazine levels. Higher thioridazine exposure increases the risk of QT prolongation and arrhythmias, and lorcaserin also has serotonergic effects.
How serious is the interaction between Lorcaserin and Thioridazine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible; if used, monitor ECG and for signs of thioridazine toxicity and consider reducing the thioridazine dose.
What other medicines interact with Thioridazine?
MediHelp also lists interactions of Thioridazine with, for example, Abiraterone, Adagrasib, Amiodarone. The full list is on the Thioridazine page.
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