Drug interactions
Givosiran + Promethazine
Severity: Moderate
Givosiran 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
Givosiran can reduce CYP2D6 activity, and promethazine is partly metabolized by CYP2D6. Higher promethazine levels may increase sedation, anticholinergic effects and QT-related risk. The clinical size of the effect is not well characterized.
What this interaction means in plain words
Givosiran 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.
Givosiran belongs to Miscellaneous; Promethazine belongs to Respiratory.
Why it happens
Givosiran reduces CYP2D6 activity, decreasing promethazine metabolism and raising its plasma concentrations.
What to do
Monitor for excess sedation, anticholinergic effects and arrhythmia, and use the lowest effective promethazine dose. Choose an alternative antiemetic if an adequate response needs high doses.
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 Givosiran
- Duloxetine + Givosiran Major
- Givosiran + Pimozide Major
- Givosiran + Propafenone Major
- Givosiran + Theophylline Major
- Givosiran + Thioridazine Major
- Givosiran + Tizanidine Major
Frequently asked questions
Can I take Givosiran with Promethazine?
MediHelp rates the interaction as moderate. Givosiran 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. Givosiran can reduce CYP2D6 activity, and promethazine is partly metabolized by CYP2D6. Higher promethazine levels may increase sedation, anticholinergic effects and QT-related risk. The clinical size of the effect is not well characterized.
How serious is the interaction between Givosiran 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: Monitor for excess sedation, anticholinergic effects and arrhythmia, and use the lowest effective promethazine dose. Choose an alternative antiemetic if an adequate response needs high doses.
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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