[1][2] Severe side effects may include urinary retention, QT prolongation, hallucinations, glaucoma, and anaphylaxis.

[4] It is also used to treat neurogenic detrusor overactivity (NDO), a form of bladder dysfunction related to neurological impairment, in children ages two years and older.

[2] With NDO, there is overactivity of the bladder wall muscle, which normally relaxes to allow storage of urine.

[2] If NDO is not treated, increased pressure in the bladder can put the upper urinary tract at risk of harm, including possible permanent damage to the kidneys.

[2] Solifenacin is also not recommended for use in people with severe liver failure, clinically significant bladder outlet obstruction in the absence of clean intermittent catheterization, decreased gastrointestinal motility (slowed intestinal contractions), or at high risk of QT prolongation (an electrical disturbance where the heart muscle takes longer than normal to recharge between beats), including people with a known history of QT prolongation and people taking medications known to prolong the QT interval.

[2] Severe allergic reactions, such as angioedema (swelling beneath the skin) and anaphylaxis, have been reported in people treated with solifenacin succinate and may be life-threatening.

When administered concomitantly with drugs that inhibit CYP3A4, such as ketoconazole, the metabolism of solifenacin is impaired, leading to an increase in its concentration in the body and a reduction in its excretion.

Because of a long elimination half life, a once-a-day dose can offer 24-hour control of the urinary bladder smooth muscle tone.

The free base is a yellow oil, while the salt solifenacin succinate forms yellowish crystals.

[13] Solifenacin was approved for medical used in the United States in 2004 with an indication to treat overactive bladder in adults 18 years and older.

[2][5] In May 2020, solifenacin was approved for medical use in the United States with an indication to treat neurogenic detrusor overactivity (NDO), a form of bladder dysfunction related to neurological impairment, in children ages two years and older.

[2] The studies were designed to measure (as a primary efficacy endpoint) the maximum amount of urine the bladder could hold after 24 weeks of treatment.