Obstetrics & Gynaecology/Urinary continence agent

Incontinence / overactive bladder drugs

also: oxybutynin · solifenacin · mirabegron · duloxetine · OAB

Overview

Drug treatment of urinary incontinence after conservative measures. The decision tree: Urge → Bladder training → antimuscarinic/mirabegron; Stress → Pelvic-floor → duloxetine.

Mechanism

Antimuscarinics (oxybutynin/solifenacin/tolterodine) block detrusor M₃ muscarinic receptors → fewer involuntary contractions (urge). Mirabegron is a β₃-adrenoceptor agonist → detrusor relaxation (storage) — an alternative when anticholinergic load is undesirable. Duloxetine (an SNRI) increases urethral sphincter tone via Onuf's nucleus → stress incontinence.

Indications

Overactive bladder / urge incontinence (after bladder training)
Stress incontinence (duloxetine, after pelvic-floor training, if surgery declined)

The agents

Oxybutyninantimuscarinic (M₃)

oral/patch

AVOID immediate-release oral in frail elderly — anticholinergic burden, falls, cognitive decline.

Solifenacin / Tolterodineantimuscarinic

oral

Better tolerated than oxybutynin.

Mirabegronβ₃ agonist

oral

No anticholinergic effects — use in frail elderly; CI in severe uncontrolled hypertension.

DuloxetineSNRI

oral

STRESS incontinence (2nd line after pelvic floor / if surgery declined).

Adverse effects

Antimuscarinics: dry mouth, constipation, blurred vision, urinary retentionclassic

Antimuscarinics: confusion/falls in the elderlyserious

Anticholinergic burden — prefer mirabegron in frail patients.

Mirabegron: hypertensionserious

Monitor BP; CI if severe uncontrolled.

Duloxetine: nausea, dry mouthcommon

Cautions & contraindications

Antimuscarinics in angle-closure glaucoma, myasthenia, significant urinary retention/GI obstructionall

Antimuscarinics (esp. oxybutynin) in frail elderlyelderly

Falls + cognitive impairment.

Mirabegron in severe uncontrolled hypertensionall

Interactions

Additive anticholinergic burden with other antimuscarinics/sedating antihistamines/TCAs

Monitoring & kinetics

Antimuscarinics: review at 4 weeks; mirabegron: BP

Oral (oxybutynin also transdermal patch — fewer anticholinergic effects).

Source: NICE NG123 — Urinary incontinence in women · BNF — Urinary frequency & incontinence