Drug interactions
Promethazine + Valerian
Severity: Moderate
Promethazine and Valerian: 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
Valerian has mild sedative properties and may add to the drowsiness caused by promethazine. This may reduce alertness and psychomotor performance.
What this interaction means in plain words
Promethazine and Valerian 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, with valerian likely acting through GABAergic mechanisms.
What to do
Advise patients to avoid driving until the effect is known. Avoid combining unless the sedation is intended and monitored.
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 Promethazine with Valerian?
MediHelp rates the interaction as moderate. Promethazine and Valerian 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. Valerian has mild sedative properties and may add to the drowsiness caused by promethazine. This may reduce alertness and psychomotor performance.
How serious is the interaction between Promethazine and Valerian?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Advise patients to avoid driving until the effect is known. Avoid combining unless the sedation is intended and monitored.
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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