Federal regulators said that they spend just as much effort and resources on evaluating a drug after it is approved as they do in the pre-approval process, according to an announcement of a report released by the U.S. Food and Drug Administration on Saturday.

The “Advances in FDA's Safety Program for Marketed Drugs” report was in response to critics who say that the agency is powerless when it comes to monitoring the safety of drugs already on the market, when industry funds paying pre-approval drug reviews shrink up.

"We think we've really balanced this," Dr. Janet Woodcock, director of the FDA’s Center for Drug Evaluation and Research, told reporters at the Association of Healthcare Journalist meeting in Atlanta, according to Reuters.

FDA said since 2008, the agency has required companies to conduct a total of 385 post-market studies as well as change drug labeling information to fit new safety guidelines 65 times.

Woodcock said four years ago, the agency could not demand label changes or mandate additional safety trials and had to, instead, depend on voluntary action from drug manufacturers.

The FDA said that its “strengthened and modernized” post-market drug safety program has resulted in a dramatic improvement in the ability of the agency’s oversight of drugs once they are made available on the market.

“Our oversight of the safety of marketed drugs has changed significantly over the past few years,” Woodcock said in a news release. “This report shows that the quality, accountability, and timeliness of post-market drug safety decisions have been enhanced, and our public communication of this information is more effective.”

FDA said that since 2008, under the Food and Drug Administration Amendments Act (FDAAA) the agency had doubled their staff at the Center for Drug Evaluation and Research from 123 in 2007 to 245 in 2012, established specific safety positions within each of its 18 divisions that review applications for new drugs, and launched new programs like Safety First, Sentinel and Safe Use.

These changes have improved the agency’s ability to track drug safety concerns, identify potential safety signals earlier, conduct more comprehensive analysis for drug clinical significance and better identify regulatory changes or other solutions that can be implemented to better protect patients from drug risks.

After an independent panel from the Institute of Medicine, which advises the government on scientific matters, recommended in 2006 that the FDA needed to do more on monitoring and evaluating the safety of medicines after they become available to the American public.

Afterwards, Congress approved the FDA Amendments Act in September 2007 which gave the watchdog agency more power to oversee drugs after approval, like ordering companies to change safety labels or conduct more safety trials and fining industry manufacturers who fail to do so.