Drug interactions
Metoclopramide intranasal + Promethazine
Severity: Major
Metoclopramide intranasal 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
Promethazine is a phenothiazine with dopamine D2 blocking activity, and metoclopramide is a D2 antagonist. Concurrent use increases the risk of extrapyramidal symptoms, tardive dyskinesia and neuroleptic malignant syndrome, as well as additive sedation.
What this interaction means in plain words
Metoclopramide intranasal 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.
Why it happens
Additive central dopamine D2 receptor antagonism.
What to do
Avoid concurrent use and choose another antiemetic, such as a 5-HT3 antagonist, if a second agent is needed. Monitor for dystonia, akathisia and parkinsonism if unavoidable.
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
Frequently asked questions
Can I take Metoclopramide intranasal with Promethazine?
MediHelp rates the interaction as major. Metoclopramide intranasal 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. Promethazine is a phenothiazine with dopamine D2 blocking activity, and metoclopramide is a D2 antagonist. Concurrent use increases the risk of extrapyramidal symptoms, tardive dyskinesia and neuroleptic malignant syndrome, as well as additive sedation.
How serious is the interaction between Metoclopramide intranasal 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 concurrent use and choose another antiemetic, such as a 5-HT3 antagonist, if a second agent is needed. Monitor for dystonia, akathisia and parkinsonism if unavoidable.
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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