Myrbetriq (mirabegron) relaxes the muscles of the urinary bladder to reduce bladder spasms. It is used to treat overactive bladder symptoms in adults, such as frequent or urgent urination and urinary incontinence, and may be combined with solifenacin (Vesicare). Myrbetriq is also used in children to treat neurogenic detrusor overactivity (NDO) caused by nerve damage from conditions like multiple sclerosis or spinal injury.