Drug interactions
Metoclopramide + Promethazine
Severity: Major
Metoclopramide and Promethazine: 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
Both drugs block dopamine receptors centrally and can cause extrapyramidal symptoms, tardive dyskinesia and neuroleptic malignant syndrome, and both cause sedation. Promethazine's anticholinergic activity may also oppose metoclopramide's prokinetic effect.
What this interaction means in plain words
Metoclopramide and Promethazine 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.
Metoclopramide belongs to Gastrointestinal Tract; Promethazine belongs to Respiratory.
Why it happens
Additive central dopamine D2 antagonism and CNS depression, with anticholinergic antagonism of prokinetic action.
What to do
Avoid using both together; choose a single antiemetic or an alternative such as a 5-HT3 antagonist. If combined, monitor for extrapyramidal symptoms and sedation.
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 Promethazine
- Cabergoline + Promethazine Contraindicated
- Dopamine + Promethazine Contraindicated
- Ibutilide + Promethazine Contraindicated
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
Other interactions of Metoclopramide
Frequently asked questions
Can I take Metoclopramide with Promethazine?
MediHelp rates the interaction as major. Metoclopramide and Promethazine 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 block dopamine receptors centrally and can cause extrapyramidal symptoms, tardive dyskinesia and neuroleptic malignant syndrome, and both cause sedation. Promethazine's anticholinergic activity may also oppose metoclopramide's prokinetic effect.
How serious is the interaction between Metoclopramide and Promethazine?
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 using both together; choose a single antiemetic or an alternative such as a 5-HT3 antagonist. If combined, monitor for extrapyramidal symptoms and sedation.
What other medicines interact with Promethazine?
MediHelp also lists interactions of Promethazine with, for example, Cabergoline, Dopamine, Ibutilide. The full list is on the Promethazine page.
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