Hello. My 96 year old mother cannot hold her urine. She wets the bed every night. She has been on various meds. Oxbutynin was one. She is currently taking 4mg of tolterodine daily but its not very effective. The doctor wants to try 25mg of Myrbetriq. Are the meds useful if she cannot even hold her urine? If they are in the same drug class, do they have the same affect on a person?