“We’ve had patients tell us they take 400 to 500 tablets day"

Which is to say: Loperamide is extremely safe at recommended doses for treating diarrhea and extremely inefficient if the goal is getting a fix. Eggleston said he’s heard of people taking 400 or 500 tablets a day. “They put it in a blender and make a smoothie and drink it over one or two hours,” he said. It causes constipation but no worse than other opioids, which people who are addicted often manage by taking stool softeners or laxatives.

Loperamide is also available as a generic, and it is cheap. You can buy 400 tablets for little more than $10 online.

Unlike opioids prescribed as painkillers, loperamide doesn’t usually reach brain cells. A naturally-occurring protein called P-glycoprotein pumps the drug out of the brain. But at very high doses, loperamide overwhelms those pumps and floods the brain’s opioid receptors. Eggleston said that’s led some people to try taking a second over-the-counter drug that disables the pumps, so they can use smaller doses of loperamide. The long-term consequences of that combination are unclear, but once in the brain, loperamide has similar effects as other opioids: drowsiness, depressed breathing, and maybe even death in the worst cases.