. >> shirley sharr is 86 years old and she takes a high dose of opioids every day, to deal with painbegan after she had knee replacement surgery 13 years ago. her morning dose is the most important. nighttime is the longest she goes without taking the medication. >> and then i take this with me when we leave to go on an errand or something. this is always in my purse. i cannot ever forget that or i'd be in trouble. >> shirley's daughter, cari, sets an alarm to remind her mother to take the next dose, in three and a half hours. over the years, shirley's doctors steadily increased her dosage because she was developing a tolerance to the medication... it wasn't as effective. >> does it still manage your pain? does it help? >> no. well it does. but i'm still always in pain. i'm never out of pain. >> i wanted to ask you about some of the side effects of the painkillers that you're on. shortness of breath to the degree that it can actually cause respiratory problems or respiratory failure. >> i'm concerned about that because i feel like i don't breathe as well. it makes me light-headed, yo