Solifenacin for Overactive Bladder: Treatment and Dosing
Start with solifenacin 5 mg orally once daily, which can be increased to 10 mg once daily if the 5 mg dose is well tolerated and additional efficacy is needed. 1
Standard Dosing Regimen
- Initial dose: 5 mg once daily taken with water and swallowed whole, with or without food 1
- Dose escalation: May increase to 10 mg once daily if the 5 mg dose is well tolerated and greater symptom control is required 1
- The 5 mg starting dose provides significant efficacy with minimal anticholinergic side effects, particularly dry mouth (7.7% vs 2.3% placebo), making it the preferred initial approach 2
Dose Modifications for Special Populations
Severe renal impairment (CrCl < 30 mL/min/1.73 m²):
- Do not exceed 5 mg once daily 1
Moderate hepatic impairment (Child-Pugh B):
- Do not exceed 5 mg once daily 1
Severe hepatic impairment (Child-Pugh C):
- Do not use solifenacin 1
Concomitant strong CYP3A4 inhibitors (e.g., ketoconazole):
- Do not exceed 5 mg once daily 1
Expected Clinical Outcomes
At the 5 mg dose, patients can expect:
- Reduction in micturitions per 24 hours by approximately 2.4 episodes (vs 0.9 with placebo) 2
- More than 50% of incontinent patients achieve complete continence after 12 weeks of treatment 3, 2
- Significant reduction in urgency episodes by 2.8 episodes (51% reduction) 2
- Significant reduction in incontinence episodes 2
- Improvements observed as early as week 2 and maintained over 12 months 4
At the 10 mg dose, additional benefits include:
- Greater reduction in micturitions (2.8 episodes per 24 hours) 2
- Significant reduction in nocturia episodes (0.71 episodes, 38.5% reduction) 2
- However, dry mouth increases to 23% (vs 7.7% at 5 mg) 2
Combination Therapy for Refractory Symptoms
If monotherapy with solifenacin 5 mg is inadequate after an appropriate trial:
- Add mirabegron 25-50 mg once daily to solifenacin 5 mg 5, 6
- The American Urological Association recommends this combination specifically for patients refractory to monotherapy, not as first-line treatment 5
- Combination therapy (solifenacin 5 mg + mirabegron 50 mg) demonstrates superior efficacy compared to either drug alone for reducing incontinence episodes, urgency, and nocturia 5, 7
- Do not skip the monotherapy trial—combination therapy is only indicated after inadequate response to single agents 5
Critical Safety Considerations and Contraindications
Absolute contraindications:
- Urinary retention 1
- Gastric retention 1
- Uncontrolled narrow-angle glaucoma 1
- Known hypersensitivity to solifenacin (risk of anaphylaxis and angioedema) 1
Important warnings:
- Angioedema can occur after the first dose or after multiple doses; promptly discontinue if tongue, hypopharynx, or laryngeal involvement occurs 1
- Not recommended in patients with clinically significant bladder outlet obstruction or decreased gastrointestinal motility 1
- Use with caution in patients being treated for controlled narrow-angle glaucoma 1
- Not recommended in patients at high risk of QT prolongation 1
- Somnolence reported—advise patients not to drive or operate heavy machinery until they know how solifenacin affects them 1
Common Pitfalls to Avoid
- Do not start at 10 mg—always begin with 5 mg to minimize anticholinergic side effects while maintaining efficacy 1
- Do not use combination therapy as first-line—reserve for patients who remain symptomatic on monotherapy 5
- Do not exceed 5 mg in patients with severe renal impairment, moderate hepatic impairment, or those taking strong CYP3A4 inhibitors 1
- Monitor for urinary retention, especially in men with bladder outlet obstruction 1