Drug interactions
Caffeine + Promethazine
Severity: Minor
Caffeine 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
Caffeine is a CNS stimulant and may partly offset promethazine-induced drowsiness. The clinical effect is modest and not clinically harmful in most patients.
What this interaction means in plain words
Caffeine 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.
Caffeine belongs to Miscellaneous; Promethazine belongs to Respiratory.
Why it happens
Pharmacodynamic opposition, with adenosine receptor antagonism by caffeine versus H1 blockade by promethazine.
What to do
No action is needed beyond awareness. Do not rely on caffeine to counter sedation when driving.
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
Other interactions of Caffeine
- Caffeine + Ephedrine Major
- Caffeine + Fezolinetant Major
- Caffeine + Methylenedioxymethamphetamine Major
- Caffeine + Selegiline transdermal Major
- Adenosine + Caffeine Moderate
- Benzphetamine + Caffeine Moderate
Frequently asked questions
Can I take Caffeine with Promethazine?
MediHelp rates the interaction as minor. Caffeine 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. Caffeine is a CNS stimulant and may partly offset promethazine-induced drowsiness. The clinical effect is modest and not clinically harmful in most patients.
How serious is the interaction between Caffeine 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: No action is needed beyond awareness. Do not rely on caffeine to counter sedation when driving.
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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