I have an illeostomy and a short bowel which constantly produces outflow Is prevalite helpful and?

Sorry, you will need to discuss this with your specialist.
See https://www.drugs.com/cdi/prevalite-powder.html

I also have 4ft. small intestine, no large, and have the same symptoms as you describe. I have no knowledge of Prevalite but will ask my doctor. I use a medicaton called Paregoric and another, Tincture of Opium. You will need to talk with your doctor about these. They have made a difference in my life. As i understand it the constant flow is just part of life with an illeostomy. Controlling it to some degree is the best you can do. I have been dealing with this for 25 yrs.& found that eating several small meals instead of one also helps. Also, what you eat & drink makes a difference. (the more in, the more out) I hope this helps you. Take care.