Following numerous reports of people taking large and sometimes toxic doses of loperamide (Imodium) to relieve symptoms of opioid withdrawal or to obtain an opioid high, the FDA said it’s working with manufacturers to alter packaging, including limits to the number of doses in a package.

Loperamide is an opioid receptor agonist that works primarily in the bowel. It is sold over the counter for treatment of diarrhea, and can be purchased in bottles containing as many as 200 caplets.