Is it ok to use imodium (loperamide) to slow bowel down when u have a colostomy.?

Yes, no for long ter. Imodim is very good, increases the tone slows down peristalsis by acting on intestinal nerve cell allows more fluid absorbed there by reducing diarrhea, how ever for long term uses being opioid receptor agonist in some will develop like drug dependency often over looked due to its benefits.
Usually. I usually advise my patients to 1st fine tune their fiber/hydration balance before resorting to medication. Imodium (loperamide) can help but you must inform your doctor if you have significant symptom change.