Suggest Treatment For Constipation After Taking Accutane

my 17 year old niece took Accutane 30 mgs for one month and had some dryness. Nothing that seemed unbearable. Now she has been increased to 60 mgs and after two weeks on the Accutane 60 mgs. she is constipated and has had blood when she tries to go. We called her dermatologist and they said to stop the medication and see her regular doctor to make sure she is okay. Can she stop Accutane without any withdrawal and how long does it take for it to completely get out of her system.. Her parents are sorry they ever started her on it and hope they have not harmed her during her taking this for the six weeks that have already passed. THey feel that the bleeding is a good enough reason to stop the medication entirely. What do you think.