Drug interactions
OnabotulinumtoxinA + Promethazine
Severity: Minor
OnabotulinumtoxinA and Promethazine: minor 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
Drugs with anticholinergic activity may theoretically add to the effects of botulinum toxin, with more pronounced neuromuscular weakness or systemic anticholinergic effects. Clinically significant cases with promethazine are not well documented.
What this interaction means in plain words
OnabotulinumtoxinA and Promethazine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
OnabotulinumtoxinA belongs to Musculoskeletal; Promethazine belongs to Respiratory.
Why it happens
Theoretical additive anticholinergic and neuromuscular effects.
What to do
No change is usually needed; watch for unusual generalized weakness, swallowing or breathing difficulty after injection.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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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 OnabotulinumtoxinA
Frequently asked questions
Can I take OnabotulinumtoxinA with Promethazine?
MediHelp rates the interaction as minor. OnabotulinumtoxinA and Promethazine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Drugs with anticholinergic activity may theoretically add to the effects of botulinum toxin, with more pronounced neuromuscular weakness or systemic anticholinergic effects. Clinically significant cases with promethazine are not well documented.
How serious is the interaction between OnabotulinumtoxinA and Promethazine?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No change is usually needed; watch for unusual generalized weakness, swallowing or breathing difficulty after injection.
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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