I Am Not Familiar With Methadone That Is Being Used

I am not familiar with methadone that is being used for cancer pain. I know it was used for other purposes but I am trying to find out if the pills we got for my mom are released over time. She is suppose to take it every 12 hours but when we gave her the pills we were given and cut them in half as we were instructed to do all the effects were multiplied. Her old meds made her a little groggy but that was expected but this was an extreme change. She couldn't form a sentence or stay awake and was extremely confused. She has had two doses and this happened both times lasting about 3 hours. I can't find much info on this particular use for methadone so I don't know what to do and the hospice nurse hasn't been helpful in answering any questions i am asking. Thank you for your input.