How long do i keep a predsol retention enema in for my doc didn't explain ?

Enemas: use as directed...Predsol retention enema is administered into the rectum to reduce inflammation associated with inflammatory bowel disease. The Prednisolone acts locally to reduce inflammation in the lower end of the bowel and the rectum. It helps relieve the symptoms of flare-ups of Crohn's disease and ulcerative colitis. One enema is administered into the rectum at night for two to four weeks.