Just when it seems that news on opioid use, prescription and abuse in this country can't get any worse, we're treated to a new revelation.

This time it comes in the form of a government report that details how prescription opioids aren't just killing people and created a new generation of drug addicts — they're costing taxpayers billions of dollars in Medicaid costs.

Last week a report from the Office of the Inspector General for the U.S. Department of Health and Human Services found that one in three Medicare beneficiaries — nearly 12 million people — received at least one opioid painkiller prescription last year. Those scripts, which came through Medicaid's Part D program, cost the government $4.1 billion, according to the report, which looked at drug records from 2006 to 2015.

“These spending trends, coupled with recent fraud cases involving compounded drugs, signal the need for action,” the office concluded.

So not only are physicians filling the medicine cabinets of older Americans with highly-addictive drugs — where, authorities say, they're often stolen by family members or the target of criminals in general — they're also sending the bill for many of those drugs along to taxpayers.

Meanwhile, thousands of people are dying each year in this opioid epidemic. There were nearly 19,000 fatal overdoses attributed to prescription opioids in 2014 alone.

At the same time, new concerns are emerging regarding the use of so-called “compounded drugs” — medications that are customized and tailored to the needs of individual patients. The drugs are created by pharmacists and physicians by combining, mixing or altering drug ingredients, according to the Inspector General's report.

Sometimes the drugs prove life-changing for patients with particular problems: A patient with swallowing difficulties is able to get his or her medication in liquid form instead of through a pill.

Other times, the drugs create public safety concerns. In 2012 compounded drugs produced by a Massachusetts-based pharmacy caused an outbreak of fungal meningitis that sickened 753 people and killed 64.

But the focus of the IG's report — and the overarching concern it creates — is the public cost associated with prescription drugs. In 2006, when the Part D program was added to Medicaid, prescription drug spending totaled $51 billion.

In 2015 that number had swelled to $137 billion with six percent — $8.4 billion — spent on controlled substances like opioids; most commonly OxyContin, Viocodin and fentanyl. Overall spending for these drugs has spiked by 165 percent since 2006, the report found.

And yet some proposed safeguards for the program — namely restricting high-risk beneficiaries to certain pharmacies or prescribers, stricter fraud reporting guidelines and a better record-keeping system — continue to go unimplemented.