The FDA-approved drug naltrexone helps people beat addiction by blocking the effects of opioids and alcohol. Yet it's not as widely known, or used, as the synthetic opioid medication methadone.
One St. Louis journalist says he's found the reason why.
"Unfortunately for naltrexone, there's just not a lot of money to be made in it," said Ben Westhoff.
In his new documentary "Antagonist," Westhoff explores the evidence of naltrexone's effectiveness at treating opioid and alcohol misuse. Many of the patients he spoke with called it a lifesaver. Westhoff also investigates how the drug got sidelined by "Big Pharma."
"As corrupt as drug trafficking is, it often seems like the drug treatment industry is almost as corrupt," he said.
By blocking opioid receptors in the brain, naltrexone suppresses cravings and prevents users from experiencing a high from opioid and alcohol use. Unlike methadone, naltrexone doesn't contain opioids, which makes it less addictive. It is also given at a less frequent rate than methadone, which is administered daily.
"In front of methadone clinics, you might see people lining up at 6 a.m. in the morning for their dosing. And because of the arcane laws, because of the lobbying organization behind methadone, a regular doctor can't just prescribe it. You have to go … to this specialized clinic," Westhoff said. "These clinics could offer naltrexone, but they don't, and part of my film is trying to figure out why. I did some investigation and found that the profit motive really is at the center of things."
The central figure in "Antagonist," Percy Menzies, has spent decades pushing for the widespread use of naltrexone. His St. Louis-based clinic Assisted Recovery Centers of America claims to have successfully treated thousands of patients with the drug since it opened in 2001. It currently serves 3,475 patients at clinics in Dellwood, St. Louis' Downtown West and a mobile unit.
Yet, for years, Menzies said he's been dismissed by others in the field of recovery.
"It is very easy to dose somebody on methadone," he said. "When you're offering an addicting drug, you don't have to do much work. People will line up at your clinic, and that's where the corruption starts."
Menzies said his clinic is focused on providing patients with choices.
"The strength of my clinic is educating our patients on the different medication paths they can take, and that is absent in our field. In our field, they just don't believe in offering them a choice. They say, 'We only believe in this,'" he said.
On a broader level, Menzies added, his clinic challenges the idea that patients in recovery need to be on medication indefinitely.
"What naltrexone debunked the myth that addiction is an incurable disease and you need to be on some substitution medication for the rest of your life," he said. "We change that [perception]. Once you get on naltrexone, you have a freedom to go out [and] work wherever you need to without cues and triggers overwhelming you."
"Antagonist" is available to stream via a Patreon membership at antagonistfilm.com.
For more on the opioid epidemic, naltrexone and the work being done at Percy Menzies' clinic, listen to St. Louis on the Air on Apple Podcasts, Spotify, YouTube or click the play button below.
"St. Louis on the Air" brings you the stories of St. Louis and the people who live, work and create in our region. The show is produced by Miya Norfleet, Emily Woodbury, Danny Wicentowski, Elaine Cha and Alex Heuer. Layla Halilbasic is our production assistant. The audio engineer is Aaron Doerr.
Copyright 2026 St. Louis Public Radio