Drug interactions
Meprobamate + Promethazine
Severity: Moderate
Meprobamate 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
Both agents are CNS depressants, so combined use can cause marked drowsiness, impaired coordination and, with higher doses, respiratory depression. Older adults are particularly vulnerable to falls and confusion.
What this interaction means in plain words
Meprobamate 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.
Why it happens
Additive CNS depression through GABAergic effects of meprobamate and H1 antagonism of promethazine.
What to do
Use the lowest effective doses and monitor sedation and respiratory function. Advise avoiding alcohol and driving.
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
- Ibutilide + Promethazine Contraindicated
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
- Amiodarone + Promethazine Major
- Amisulpride + Promethazine Major
Frequently asked questions
Can I take Meprobamate with Promethazine?
MediHelp rates the interaction as moderate. Meprobamate 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. Both agents are CNS depressants, so combined use can cause marked drowsiness, impaired coordination and, with higher doses, respiratory depression. Older adults are particularly vulnerable to falls and confusion.
How serious is the interaction between Meprobamate 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 sedation and respiratory function. Advise avoiding alcohol and 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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