IM works best if you are trained to give injections, this way the medication does not go through the intestines. If you have Crohn's with an ileostomy, the large intestine absorbs anything ingested. This is why medication dosages may change depending on if the disease is active or in remission. I have taken pills for Crohn's and they were not absorbed. I could tell this as I saw the whole medication in my ileostomy output. Everyone is different. I have lived with Crohn's for 50 years.