Drug interactions
Chlordiazepoxide + Promethazine
Severity: Moderate
Chlordiazepoxide and Promethazine: moderate 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 and the benzodiazepine chlordiazepoxide produce additive sedation and psychomotor impairment. Excessive CNS and respiratory depression can occur, especially in elderly or frail patients.
What this interaction means in plain words
Chlordiazepoxide and Promethazine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Chlordiazepoxide belongs to Central Nervous System; Promethazine belongs to Respiratory.
Why it happens
Additive CNS depression via H1 antagonism and GABA-A potentiation.
What to do
Use the lowest effective doses and monitor for oversedation and respiratory depression. Counsel patients to avoid driving and alcohol.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Chlordiazepoxide
Frequently asked questions
Can I take Chlordiazepoxide with Promethazine?
MediHelp rates the interaction as moderate. Chlordiazepoxide and Promethazine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Promethazine and the benzodiazepine chlordiazepoxide produce additive sedation and psychomotor impairment. Excessive CNS and respiratory depression can occur, especially in elderly or frail patients.
How serious is the interaction between Chlordiazepoxide and Promethazine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use the lowest effective doses and monitor for oversedation and respiratory depression. Counsel patients to avoid driving and alcohol.
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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