Loperamide is an over-the-counter anti-diarrheal medication that is available in tablet, capsule, or liquid form under brand names such as Imodium, Kaopectate 1-D, Maalox Anti-Diarrheal, and Pepto Diarrhea Control. Because it acts at mu-opioid receptors, which regulate movement in the intestinal tract, it is an opioid medication, and there are reports of its being misused by drug users to stave off opioid withdrawal or possibly even to get high.
Misuse of loperamide has been reported since 2003; it is not common, but it has been reported all over the country. Nationwide, the number of calls to poison centers involving the intentional abuse or misuse of loperamide increased from 87 in 2010 to 190 in 2014 (AAPCC annual reports; http://www.aapcc.org/annual-reports/).
Effects of Loperamide
When taken as recommended, loperamide is designed not to enter the brain; but instructions available on the Internet purport to show how taking loperamide in very high quantities and combining it with other substances may help it produce psychoactive effects that resemble the euphoric effects of other opioids or that mitigate cravings and withdrawal symptoms.
Users’ reports of these effects (if any) are conflicting, but physical consequences of loperamide misuse may be severe, including fainting, abdominal pain, constipation, cardiovascular toxicity (including racing heart and even cardiac arrest), pupil dilation, and kidney failure from urinary retention. Anecdotes and case reports indicated that the potential harm is high.
There were also reports of opioid withdrawal symptoms when users stopped taking loperamide, including severe anxiety, vomiting, and diarrhea.
FDA issued a Safety Alert about Loperamide on 6/7/16: Loperamide (Imodium): Drug Safety Communication - Serious Heart Problems With High Doses From Abuse and Misuse.