darifenacin hydrobromide: clinical use

Prescribing considerations

• Exclude or address other causes of frequency, including urinary infection, renal disease and heart failure.
• Assess bladder-outflow obstruction, urinary-retention risk, severe constipation and impaired gastrointestinal motility.
• Review hepatic impairment, cardiac disease, glaucoma treatment and total anticholinergic burden.
• Safety and efficacy are not established for neurogenic detrusor overactivity or in people under 18.

Contraindications and cautions

• Hypersensitivity to darifenacin or an excipient
• Urinary or gastric retention
• Uncontrolled narrow-angle glaucoma
• Myasthenia gravis
• Severe hepatic impairment
• Severe ulcerative colitis or toxic megacolon
• Concurrent potent CYP3A4 inhibition

Monitoring

• Review symptom response and tolerability, including dry mouth and constipation.
• Check for urinary retention, worsening gastrointestinal obstruction and neuropsychiatric effects.
• Use therapeutic drug monitoring for digoxin when darifenacin is started, stopped or altered.

Clinical pharmacology

Darifenacin is a selective M3 muscarinic receptor antagonist in vitro. It undergoes extensive hepatic and intestinal metabolism through CYP3A4 and CYP2D6, moderately inhibits CYP2D6 and is highly protein bound.

Formulation and product differences

• The product is a prolonged-release film-coated tablet.
• It must not be chewed, divided or crushed.
• It may be taken with or without food.

Modified-release tablet

Route: Oral

Strengths: 7.5 mg, 15 mg