Anticholinergic — Antispasmodic (Muscarinic Antagonist) Pregnancy: There are no adequate data on the use of oxybutynin in pregnant women; studies in animals have shown minor reproductive toxicity. Oxybutynin is not recommended during pregnancy. Breast-feeding: a small amount is excreted in the mother's milk and the effect on newborns/infants is unknown, so use during breastfeeding is not recommended. Fertility: reproduction studies with oral oxybutynin in the mouse, rat, hamster and rabbit showed no evidence of impaired fertility.

Oxybutynin (OAB — Anticholinergic Caution in Elderly)

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

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

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Prolonged-release tablets. Starting dose: one 5 mg tablet once daily. Maintenance/dose adjustment: after at least one week on 5 mg daily the dose may be increased to 10 mg once daily, with subsequent incremental increases or decreases of 5 mg/day and an interval of at least one week between dose changes, to achieve an optimal balance of efficacy and tolerability. Elderly: no dosage adjustment is necessary in elderly patients.

Route: Oral — prolonged-release tablets swallowed whole with the aid of liquid; must not be chewed, divided or crushed. May be given with or without food.

Frequency: Once daily

Max: In patients requiring a higher dose, the total daily dose should not exceed 20 mg

Source: eMC SPC for Oxybutynin hydrochloride 10 mg prolonged-release tablets. IMPORTANT FORMULATION CAVEAT: these figures are for the PROLONGED-RELEASE (once-daily) preparation. Immediate-release oxybutynin has a different SPC and a different dosing schedule, which is not covered by this record. For patients currently taking immediate-release oxybutynin, clinical judgement should be exercised in selecting the appropriate prolonged-release dose, adjusting to the minimum dose that achieves an optimal balance of efficacy and tolerability, taking into account the current immediate-release dose. Missed dose: the patient should wait and take the next dose at the regular time. ELDERLY (the focus of this page): SPC 4.2 states no dosage adjustment is necessary, but SPC 4.4 warns that oxybutynin should be used with caution in the frail elderly who may be more sensitive to its effects, that anticholinergics should be used with caution in elderly patients due to the risk of cognitive impairment, and that caution is needed in pre-existing dementia treated with cholinesterase inhibitors due to the risk of aggravation of symptoms. Anticholinergic CNS effects (hallucinations, agitation, confusion, somnolence) have been reported — monitoring is recommended especially in the first few months after initiating therapy or increasing the dose, and discontinuation or dose reduction should be considered if they develop. SPC 4.8 lists pseudo-obstruction as a risk in patients who are elderly or constipated and taking other medicines that decrease intestinal motility. Angioedema of the face, lips, tongue and/or larynx has been reported, sometimes after the first dose — discontinue promptly and secure the airway if the tongue, hypopharynx or larynx is involved. Visual acuity and intraocular pressure should be monitored periodically as oxybutynin can cause angle-closure glaucoma. Heat: use in fever or high environmental temperature can cause heat prostration or heat stroke due to decreased sweating. Patients with rare hereditary galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine. Paediatric (SPC 4.2, not per kg): children over the age of 5 years — initial dose of 5 mg once a day, increased in 5 mg increments up to a maximum of 15 mg once a day; oxybutynin should not be used in children below the age of 5 years because safety and efficacy have not been established. Verify against a children's formulary before prescribing for a child. The openFDA US label (extended-release, maximum 30 mg/day in adults) was fetched as a cross-check only and was NOT used — the UK SPC maximum is 20 mg/day.

Dose adjustments

Renal

No numerical renal dose adjustment is given in this SPC. SPC 4.4: oxybutynin should be given with caution in patients with hepatic or renal impairment. Note that urinary frequency and nocturia due to renal failure is listed as a contraindication (SPC 4.3).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm 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.

Contraindications

Hypersensitivity to the active substance(s) or to any of the excipients
Narrow-angle glaucoma or shallow anterior chamber
Myasthenia gravis
Urinary retention
Gastrointestinal obstructive disorder, paralytic ileus or intestinal atony
Severe ulcerative colitis
Toxic megacolon
Urinary frequency and nocturia due to heart or renal failure
Porphyria

Side effects

Most common (more than 5% of patients in clinical trials): dry mouth, constipation, diarrhoea, headache, somnolence and dizziness
Anticholinergic CNS effects (serious): hallucinations, confusional state, agitation, memory impairment; also psychotic disorder, anxiety, nightmares, paranoia, symptoms of depression and cognitive disorders
Gastrointestinal: gastro-oesophageal reflux disease, abdominal pain, dyspepsia, nausea, flatulence, dysphagia, vomiting; pseudo-obstruction in patients at risk (elderly, or patients with constipation taking other medicines that decrease intestinal motility)
Renal and urinary: dysuria, urinary hesitation, urinary retention, residual urine
Eye: vision blurred, dry eye; angle closure glaucoma, mydriasis, ocular hypertension
Skin and immune: dry skin, pruritus, urticaria, rash; angioedema and hypohidrosis; hypersensitivity and anaphylactic reaction. Other: heat stroke and falls

Interactions

Cholinesterase inhibitors — caution in patients with pre-existing dementia treated with cholinesterase inhibitors, due to the risk of aggravation of symptoms (SPC 4.4)
Bisphosphonates and other medicinal products that can cause or exacerbate oesophagitis — anticholinergics should be used with caution in patients concurrently taking them, and in patients with hiatal hernia or gastro-oesophageal reflux (SPC 4.4)
Other medicinal products that decrease intestinal motility — pseudo-obstruction has been reported in at-risk patients (elderly, or patients with constipation) taking such products (SPC 4.8)
Section 4.5 (interactions) was not captured in the fetched eMC bundle — check the full interaction list against the SPC before publication
Cross-check (US label, not eMC): co-administration with other anticholinergic drugs may increase the frequency and/or severity of anticholinergic effects; potent CYP3A4 inhibitors (e.g. ketoconazole, itraconazole, miconazole, erythromycin, clarithromycin) can approximately double mean oxybutynin plasma concentrations; anticholinergics may alter absorption of concomitant drugs with a narrow therapeutic index and antagonise prokinetic agents such as metoclopramide

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. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways