Drug interactions
Loxapine inhaled + Promethazine
Severity: Moderate
Loxapine inhaled 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 drugs block dopamine receptors and cause sedation, so together they may increase drowsiness and extrapyramidal symptoms, and rarely neuroleptic malignant syndrome. Inhaled loxapine can also cause bronchospasm, and additive CNS depression may complicate monitoring.
What this interaction means in plain words
Loxapine inhaled 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 dopamine D2 antagonism and CNS depression.
What to do
Monitor for oversedation, movement disorders and signs of neuroleptic malignant syndrome such as fever and rigidity. Use the lowest effective doses and avoid other sedatives where possible.
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 Loxapine inhaled with Promethazine?
MediHelp rates the interaction as moderate. Loxapine inhaled 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 drugs block dopamine receptors and cause sedation, so together they may increase drowsiness and extrapyramidal symptoms, and rarely neuroleptic malignant syndrome. Inhaled loxapine can also cause bronchospasm, and additive CNS depression may complicate monitoring.
How serious is the interaction between Loxapine inhaled 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 oversedation, movement disorders and signs of neuroleptic malignant syndrome such as fever and rigidity. Use the lowest effective doses and avoid other sedatives where possible.
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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