WASHINGTON (AP) — Medicare's popular prescription program has an unsavory underside. It's an easy target for drug abusers seeking to feed their own addictions or sell painkillers for profit, congressional investigators said in a report released Tuesday.

The Government Accountability Office found that about 170,000 Medicare recipients each received prescriptions from multiple doctors for 14 frequently abused medications in 2008. Not counting related charges for office visits, the cost to the taxpayer-supported program amounted to $148 million.

Abuse of prescription medications is a fast-growing drug problem, particularly entrenched among teens and young adults. Sen. Tom Carper, D-Del., who requested investigation, said Medicare has a responsibility to not make things any worse.