The FDA sent a warning letter to EPH Technologies, accusing it of marketing and selling unapproved drugs.

The products are sold under the names Detoxoplex, Sinoplex and Migrenza, and are marketed for a number of conditions, including migraines and opioid withdrawal symptoms.

According to EPH Technologies' website, Detoxoplex can reduce "symptoms typically associated with withdrawal from opioid use."

In Tuesday's letter, the FDA said the product has not been determined to be safe and effective for these uses. "Further, this unproven treatment could cause patients to forgo or delay FDA-approved treatments for opioid addiction and withdrawal," it said. "The marketing and sale of unapproved opioid addiction treatment products is a potentially significant threat to the public health."