Drug interactions
Lorcaserin + Promethazine
Severity: Minor
Lorcaserin and Promethazine: minor 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 is a CYP2D6 inhibitor and promethazine is partly metabolised by CYP2D6, so exposure to promethazine could rise modestly. Lorcaserin has been withdrawn from many markets, and a clinically important effect is not firmly established.
What this interaction means in plain words
Lorcaserin and Promethazine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Why it happens
Inhibition of CYP2D6-mediated metabolism of promethazine by lorcaserin.
What to do
Monitor for increased sedation or anticholinergic effects and reduce the promethazine dose if they occur. No routine adjustment is needed.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Promethazine
- Ibutilide + Promethazine Contraindicated
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
- Amiodarone + Promethazine Major
- Amisulpride + Promethazine Major
Frequently asked questions
Can I take Lorcaserin with Promethazine?
MediHelp rates the interaction as minor. Lorcaserin and Promethazine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Lorcaserin is a CYP2D6 inhibitor and promethazine is partly metabolised by CYP2D6, so exposure to promethazine could rise modestly. Lorcaserin has been withdrawn from many markets, and a clinically important effect is not firmly established.
How serious is the interaction between Lorcaserin and Promethazine?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for increased sedation or anticholinergic effects and reduce the promethazine dose if they occur. No routine adjustment is needed.
What other medicines interact with Promethazine?
MediHelp also lists interactions of Promethazine with, for example, Ibutilide, Pimozide, Thioridazine. The full list is on the Promethazine page.
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