In a letter sent Tuesday, the Food and Drug Administration (FDA) directed companies to stop selling or marketing drugs that are made from fentanyl, a synthetic opioid.
The letter follows an FDA advisory published in September saying that the drug can cause cardiac arrest in those over 65.
The FDA said that the company was required to send the letter by Feb. 1, 2019.
The agency is in the midst of reviewing more than 100 opioid-related deaths linked to the drug.
The advisory said that some opioid drugs contain fentanyl and that “some manufacturers are using it to make their own opioids.”
The letter went on to say that some drugs, such as OxyContin, have been marketed to patients who had suffered fentanyl overdoses, which can cause death if not treated quickly.
In August, the FDA said it would not ban the drug, saying that some of the medications may be safe and effective.
The company that made OxyContin stopped selling the drug in October.