Drug interactions
Carbachol + Oxybutynin
Severity: Moderate
Carbachol and Oxybutynin: 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
Carbachol is a direct-acting muscarinic agonist, whereas oxybutynin blocks muscarinic receptors. Given together, each can blunt the effect of the other, so the therapeutic action of carbachol (for example bladder contraction or pupillary miosis) may be reduced.
What this interaction means in plain words
Carbachol and Oxybutynin 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.
Carbachol belongs to Miscellaneous; Oxybutynin belongs to Genitourinary.
Why it happens
Pharmacodynamic antagonism at muscarinic receptors between a cholinergic agonist and an antimuscarinic.
What to do
Avoid combining where possible; if both are required, monitor for loss of carbachol effect and adjust the dose or choose a non-opposing agent.
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 Oxybutynin
Other interactions of Carbachol
- Atropine + Carbachol Moderate
- Bethanechol + Carbachol Moderate
- Carbachol + Darifenacin Moderate
- Carbachol + Dicyclomine Moderate
- Carbachol + Donepezil Moderate
- Carbachol + Flavoxate Moderate
Frequently asked questions
Can I take Carbachol with Oxybutynin?
MediHelp rates the interaction as moderate. Carbachol and Oxybutynin 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. Carbachol is a direct-acting muscarinic agonist, whereas oxybutynin blocks muscarinic receptors. Given together, each can blunt the effect of the other, so the therapeutic action of carbachol (for example bladder contraction or pupillary miosis) may be reduced.
How serious is the interaction between Carbachol and Oxybutynin?
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 combining where possible; if both are required, monitor for loss of carbachol effect and adjust the dose or choose a non-opposing agent.
What other medicines interact with Oxybutynin?
MediHelp also lists interactions of Oxybutynin with, for example, Bethanechol, Clozapine, Potassium chloride. The full list is on the Oxybutynin page.
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