What is the recommended dose of solifenacin (VESIcare) for patients with impaired renal function?

Solifenacin Dosing in Renal Insufficiency

For patients with severe renal impairment (creatinine clearance <30 mL/min), the maximum recommended dose of solifenacin is 5 mg once daily. 1

Dosing Recommendations Based on Renal Function

• For patients with normal renal function or mild to moderate renal impairment (creatinine clearance ≥30 mL/min), the standard dosing of solifenacin (5-10 mg once daily) can be used 1, 2
• For patients with severe renal impairment (creatinine clearance <30 mL/min), the maximum dose should be limited to 5 mg once daily 1, 3
• Solifenacin displays higher exposure and prolonged half-life in patients with renal impairment, especially severe renal impairment 3

Pharmacokinetic Considerations

• Solifenacin is eliminated mainly through hepatic metabolism via cytochrome P450 (CYP) 3A4, with only about 7% (range 3-13%) of the dose being excreted unchanged in the urine 2
• Despite the relatively low renal elimination, studies have shown that exposure to solifenacin increases approximately 2-fold in patients with severe renal impairment 2, 3
• The elimination half-life of solifenacin is prolonged in patients with renal disease:
  • Normal renal function: 68.2 ± 27.2 hours
  • Mild renal impairment: 89.1 ± 34.5 hours
  • Moderate renal impairment: 90.6 ± 27.3 hours
  • Severe renal impairment: 111 ± 38.3 hours 3

Monitoring Recommendations

• Creatinine clearance should be calculated using the Cockcroft-Gault formula rather than just relying on serum creatinine for determining appropriate medication dosages in renal impairment 4
• For borderline renal function, a 24-hour urine collection may be needed to more accurately define the degree of renal insufficiency prior to making dosing decisions 4
• Monitor patients for increased anticholinergic side effects, which may be more pronounced in patients with renal impairment due to higher drug exposure 2, 5

Common Side Effects to Monitor

• Dry mouth (reported in 26.8% of patients taking solifenacin) 5
• Constipation (reported in 17.1% of patients) 5
• Blurred vision (reported in 3.5% of patients) 5

Clinical Efficacy Considerations

• Despite the need for dose adjustment in severe renal impairment, solifenacin remains effective for treating overactive bladder symptoms at the 5 mg dose 2, 5
• The 5 mg dose has been shown to significantly reduce urinary frequency, urgency episodes, and incontinence episodes compared to placebo 5
• Approximately 53% of patients with incontinence at baseline achieved complete continence with solifenacin treatment 5

Important Cautions

• Avoid exceeding the 5 mg daily dose in patients with severe renal impairment to prevent excessive drug accumulation and potential toxicity 1, 3
• Consider the potential for drug interactions, particularly with CYP3A4 inhibitors, which could further increase solifenacin exposure in patients with renal impairment 2
• The FDA label specifically states that the maximum recommended dose for patients with severe renal impairment is 5 mg once daily 1