Solifenacin: clinical use

Prescribing considerations

• Exclude or manage other causes of urinary frequency, including urinary infection, heart failure and renal disease.
• Assess bladder-outflow obstruction, gastrointestinal obstruction or reduced motility, renal and hepatic function, anticholinergic burden and relevant QT-risk factors.
• Review effectiveness and tolerability; monitor constipation, urinary retention, visual symptoms and cognitive or anticholinergic adverse effects.
• For paediatric neurogenic detrusor overactivity, use the licensed oral suspension with specialist prescribing and periodic review.

Contraindications and cautions

• Urinary retention when treating overactive bladder.
• Severe gastrointestinal disease, including toxic megacolon; myasthenia gravis; narrow-angle glaucoma; or significant risk of these conditions.
• Hypersensitivity to solifenacin or formulation excipients.
• Haemodialysis or severe hepatic impairment.
• Severe renal impairment or moderate hepatic impairment combined with a potent CYP3A4 inhibitor.

Monitoring

• Symptom response and ongoing need for treatment.
• Bowel function and signs of gastrointestinal obstruction or faecal impaction.
• Ability to empty the bladder, particularly with bladder-outflow obstruction.
• Renal and hepatic status where impaired or changing.
• ECG or electrolyte risk assessment when clinically indicated by long-QT, hypokalaemia or other arrhythmia risk factors.
• Growth, tolerability, urinary infections and QT findings in children receiving oral suspension for neurogenic detrusor overactivity.

Clinical pharmacology

Solifenacin is a competitive muscarinic receptor antagonist. It is extensively metabolised in the liver, mainly through CYP3A4, and has a terminal half-life of approximately 45 to 68 hours.

Formulation and product differences

• The film-coated tablet should be swallowed whole and may be taken with or without food; it contains lactose.
• The orange-flavoured oral suspension requires accurate measurement with an oral syringe and adaptor.
• Oral suspension should be followed by water and not taken together with food or other drinks.
• Only the oral suspension described here includes the paediatric licence for neurogenic detrusor overactivity from age 2 years.
• The suspension contains xylitol, propylene glycol, parabens and a very small amount of benzyl alcohol; these may be relevant to individual tolerability or allergy assessment.

Oral suspension

Route: Oral

Strengths: 1 mg/mL

Tablet

Route: Oral

Strengths: 5 mg, 10 mg