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Anticholinergic — Antispasmodic (Muscarinic Antagonist)

Oxybutynin (OAB — Anticholinergic Caution in Elderly)

Brand names: Ditropan, Kentera (patch), Lyrinel XL

Oxybutynin is an antimuscarinic used for the symptoms of overactive bladder.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

Oxybutynin chloride extended-release tablets must be swallowed whole with the aid of liquids, and must not be chewed, divided, or crushed. Oxybutynin chloride extended-release tablets may be administered with or without food. Oxybutynin chloride extended-release tablets must be swallowed whole with the aid of liquids, and must not be chewed, divided, or crushed. Oxybutynin chloride extended-release tablets may be administered with or without food. (2) Adults: Start with 5 mg or 10 mg, once daily at approximately the same time every day. Dose should not exceed 30 mg per day. ( 2.1 ) Pediatric patients (6 years of age or older): Start with 5 mg, once daily at approximately the same time every …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2023-05-31. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

It blocks muscarinic receptors in the bladder, reducing detrusor overactivity; it also has direct smooth-muscle relaxant effects.

Prescribing in practice

  • It has a high anticholinergic burden and crosses into the brain — it is best avoided in frail older patients (confusion, falls), where alternatives or the transdermal form may be preferable.
  • Avoid in narrow-angle glaucoma, significant urinary retention and gastrointestinal obstruction.
  • Dry mouth and constipation are common.

Monitoring

Review symptom benefit and anticholinergic effects, particularly cognition in older patients.

Counselling the patient

  • Dry mouth and constipation are common.
  • Report new confusion or difficulty passing urine.

Evidence & guidelines

An antimuscarinic for overactive bladder (NICE NG123), used cautiously in older people because of anticholinergic burden.

Reference: AGS Beers Criteria 2023; STOPP/START v3 2023; MHRA Drug Safety Update 2021 (anticholinergic drugs and dementia risk); NICE CG171 (Urinary Incontinence); Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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