Emily started Pulmozyme 13 days after it came on the market and has been on it ever since. She is 22 now and we can't remember exactly when it came out, but we think she's been on it since she was about 9. She is very faithful to it because she knows if she misses a day, she regrets it. It helps her alot to cough up the crap that loosens up when Mike gives her physical therapy. Sometimes when she is feeling really lousy, she will up it to twice a day.