solifenacin

Solifenacin is a prescription medicine used to treat symptoms of overactive bladder in adults, including urinary urgency, frequency, and urge incontinence. It is marketed in several places under the brand name Vesicare and as a generic medication in appropriate formulations.

Solifenacin belongs to the antimuscarinic (anticholinergic) class and acts as a selective antagonist of muscarinic receptors, with preference for the M3 subtype found in the detrusor muscle of the bladder. By blocking these receptors, solifenacin reduces involuntary bladder contractions and increases bladder capacity, helping to decrease episodes of urgency and incontinence.

The drug is taken by mouth as solifenacin succinate. It has a relatively long duration of action, with peak levels in a few hours after dosing and an elimination half-life of about 45 hours. It is primarily metabolized in the liver by the enzyme CYP3A4 and is excreted in both urine and feces. Dose adjustments may be needed for liver impairment. Typical initial dosing is 5 mg once daily, which can be increased to 10 mg daily based on response and tolerability; it may be reduced or avoided in moderate to severe hepatic impairment. Strong inhibitors of CYP3A4 (for example certain antifungals or HIV protease inhibitors) can raise solifenacin levels and may require dose adjustment.

Common side effects include dry mouth, constipation, blurred vision, and urinary retention. Other risks include headache and, particularly in older patients, possible cognitive effects or confusion. Solifenacin should be avoided in individuals with urinary retention, significant gastric motility disorders, uncontrolled narrow-angle glaucoma, or severe hepatic impairment. Pregnancy data are limited; use during pregnancy should be limited to those of clear benefit. The elderly may require careful monitoring for anticholinergic effects.