Drug interactions
Carbinoxamine + Promethazine
Severity: Moderate
Carbinoxamine 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 are sedating first-generation antihistamines with anticholinergic effects. Taking them together increases drowsiness, dry mouth, urinary retention and confusion, with particular risk in the elderly and children.
What this interaction means in plain words
Carbinoxamine 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.
Carbinoxamine belongs to Respiratory; Promethazine belongs to Respiratory.
Why it happens
Additive H1 antagonism, CNS depression and antimuscarinic effects.
What to do
Avoid duplicate antihistamine therapy and use only one agent. Monitor for oversedation and anticholinergic effects if both are used.
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 Carbinoxamine
- Alprazolam + Carbinoxamine Moderate
- Amisulpride + Carbinoxamine Moderate
- Amitriptyline + Carbinoxamine Moderate
- Amobarbital + Carbinoxamine Moderate
- Asenapine + Carbinoxamine Moderate
- Azelastine-fluticasone + Carbinoxamine Moderate
Frequently asked questions
Can I take Carbinoxamine with Promethazine?
MediHelp rates the interaction as moderate. Carbinoxamine 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 are sedating first-generation antihistamines with anticholinergic effects. Taking them together increases drowsiness, dry mouth, urinary retention and confusion, with particular risk in the elderly and children.
How serious is the interaction between Carbinoxamine 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: Avoid duplicate antihistamine therapy and use only one agent. Monitor for oversedation and anticholinergic effects if both are used.
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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