Sept. 28 (UPI) — The U.S. Food and Drug Administration approved nearly 50 new prescription opioid pain medications between 1997 and 2018, even though it lacked “critical” data on safety and effectiveness, an analysis published Monday by the journal Annals of Internal Medicine found.

None of the 48 drugs granted agency approval during the more than 20-year period was evaluated in clinical trials that lasted longer than 12 weeks, and the trials often included narrowly defined groups of patients, researchers said.

And few included “systematic assessments” of risks associated with these medications, including addiction potential and non-medical use.

“Our analysis provides a window through which to view the FDA’s opioid regulation over the past 20 years,” study co-author Dr. Caleb Alexander, founding co-director of the Center for Drug Safety and Effectiveness at Johns Hopkins Bloomberg School of Public Health, told UPI.

“We found the FDA often approved new opioids based