Because there is no published experience with solifenacin during breastfeeding and it has a long half-life averaging 55 hours, an alternate drug may be preferred, especially while nursing a newborn or preterm infant. Long-term use of solifenacin might reduce milk production or milk letdown. During long-term use, observe the infant for signs of decreased milk production (e.g., insatiety, poor weight gain) and for anticholinergic symptoms (e.g., constipation, urinary retention, UTI, dry mouth).