Suggest Medication For Chronic Constipation For A 4 Year Old

my daughter has suffered chronic constipation from 4 weeks old and she is now 4 and a half,she has had many enema's due to faecal impaction she is only daily dose of 4 sachets of movicol peadiactric plan,that amount of doses did seem to give a normal bowel function up until 9 days ago, the amount of faeces she was emptying from her bowel started to get less and less so i put the dosage up but now for the last 5 days she has became faecal impacted and there is a very very large mass in her, i can feel a large mass in her abdomen she has managed to push so hard at the toilet that it started to come out her rectum but its so large its stuck and it keeps going back up and she cant push it out any further,she is in a great deal of pain tonight, i am going to take her right to the ward that she attends in the morning is there anything i can do for her tonight to ease her of this discomfort, or anything that can be done to avoid an emena as is its very disturbing for her to go through enema's all the time. thanks