lactulose

is lactulose made for everyone with liver problems? my mom is very sick. her ammonia level was at 80 when she got tested then it went down to 53 she was still not feeling to good but they send her home they said to make sure that she has 3 to 4 bm everyday she has been taking lactulose for a few months now but she went home and she still did not have a bm  the next day and she got really bad. so we took her back to the hospital and they tested her again. it was at 147 in less than 24 hrs it had trippled. well they gave her an enima and she took the biggest bm that the rn that gave it to her said it was the biggest she has seen so she was really backed up. and later that day they gave her another. and she was still goin. well the dr got after her and me thinking that i did not follow the instruction as she said but i did. my mom just didnt has a bm. i just want to know is lactulose made for everyone if its suppose to work that good then why was she so backed up.