Drug interactions
Promethazine + Rolapitant
Severity: Moderate
Promethazine and Rolapitant: 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
Rolapitant is a long-acting CYP2D6 inhibitor and may raise concentrations of CYP2D6 substrates. Promethazine is partly metabolized by CYP2D6, so exposure and adverse effects such as sedation may increase.
What this interaction means in plain words
Promethazine and Rolapitant 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 belongs to Respiratory; Rolapitant belongs to Gastrointestinal Tract.
Why it happens
Rolapitant inhibits CYP2D6, reducing promethazine metabolism.
What to do
Monitor for excess sedation and anticholinergic effects, and consider a lower promethazine dose. The inhibition may persist for several weeks after rolapitant.
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
Other interactions of Rolapitant
- Pimozide + Rolapitant Contraindicated
- Rolapitant + Thioridazine Contraindicated
- Atomoxetine + Rolapitant Major
- Deutetrabenazine + Rolapitant Major
- Eliglustat + Rolapitant Major
- Flecainide + Rolapitant Major
Frequently asked questions
Can I take Promethazine with Rolapitant?
MediHelp rates the interaction as moderate. Promethazine and Rolapitant 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. Rolapitant is a long-acting CYP2D6 inhibitor and may raise concentrations of CYP2D6 substrates. Promethazine is partly metabolized by CYP2D6, so exposure and adverse effects such as sedation may increase.
How serious is the interaction between Promethazine and Rolapitant?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for excess sedation and anticholinergic effects, and consider a lower promethazine dose. The inhibition may persist for several weeks after rolapitant.
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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