What is Vesicare (solifenacin)?

Solifenacin (Vesicare): An Antimuscarinic for Overactive Bladder

Solifenacin (Vesicare) is a muscarinic receptor antagonist FDA-approved for the treatment of adults with overactive bladder with symptoms of urge urinary incontinence, urgency, and urinary frequency. 1

Mechanism of Action and Pharmacology

• Solifenacin is a competitive M3 receptor antagonist that works by blocking muscarinic receptors in the bladder, reducing involuntary detrusor muscle contractions 2
• It has a long half-life of 33-85 hours, allowing for convenient once-daily dosing 2
• Solifenacin has high bioavailability (approximately 90%) that is not affected by food intake 2
• The drug is primarily metabolized through hepatic pathways via CYP3A4, with only about 7% excreted unchanged in urine 2

Clinical Applications

• Solifenacin is indicated as second-line therapy for overactive bladder after behavioral therapies have been tried 3
• It is effective for both "wet" OAB (with incontinence) and "dry" OAB (without incontinence) 4
• Available in two dosage strengths: 5 mg and 10 mg once-daily tablets 1
• Therapeutic effects typically begin within 2-4 weeks of treatment and are maintained with long-term therapy 2

Efficacy

• Solifenacin demonstrates efficacy for all symptoms of overactive bladder, including:
  • Reduction in urinary incontinence episodes 3
  • Decrease in urgency episodes 3
  • Reduction in urinary frequency 3
  • Improvement in nocturia 3
• When combined with mirabegron (a β3-adrenoceptor agonist), solifenacin shows enhanced efficacy for patients refractory to monotherapy 3
• The combination of solifenacin 5 mg plus mirabegron 50 mg has demonstrated superior efficacy to either medication alone in reducing incontinence episodes and micturitions 3

Safety Considerations and Contraindications

• Solifenacin is contraindicated in patients with:
  • Urinary retention 1
  • Gastric retention 1
  • Uncontrolled narrow-angle glaucoma 1
  • Known hypersensitivity to solifenacin 1
• Use with extreme caution in patients with:
  • Impaired gastric emptying 3
  • History of urinary retention 3
  • Narrow-angle glaucoma (only with ophthalmologist approval) 3

Common Adverse Effects

• Dry mouth (most common adverse effect, generally mild) 4, 5
• Constipation 1
• Blurred vision 1
• Dry eyes 1
• Decreased sweating (caution in hot environments due to risk of heat prostration) 1

Special Populations

• Elderly patients: Exposure to solifenacin is increased approximately 1.2-fold in elderly subjects, but dosage adjustment is generally not required 2
• Hepatic impairment: Doses exceeding 5 mg/day are not recommended for patients with moderate hepatic impairment (Child-Pugh score 7-9) 2
• Renal impairment: Doses exceeding 5 mg/day are not recommended for patients with severe renal impairment (creatinine clearance <30 mL/min) 2

Comparative Tolerability

• Solifenacin 5 mg/day is better tolerated than oxybutynin immediate release 15 mg/day, with fewer episodes and lower severity of dry mouth in both younger (≤65 years) and older (>65 years) patients 5
• Solifenacin appears to have better long-term tolerability than immediate-release oxybutynin and tolterodine based on withdrawal rates due to adverse effects 2

Patient-Reported Outcomes

• Treatment with solifenacin is associated with significant improvements in:
  • Patient perception of bladder condition 6
  • Health-related quality of life 6
  • Reduction in symptom bother 6

Practical Considerations

• Patients should be advised that solifenacin may cause blurred vision or drowsiness and should exercise caution when driving or operating machinery 1
• If a dose is missed, patients should take the next dose as scheduled and not double the dose 1
• Patients should be instructed to discontinue solifenacin and seek immediate medical attention if they experience edema of the tongue or laryngopharynx, or difficulty breathing 1