The amendment, introduced by Sen. Joe Manchin, D-W.Va., would reclassify painkillers like Vicodin and Lortab as Schedule II drugs, which also affects how they are to be stored and prescribed.

For instance, patients would need an original prescription for refills, hydrocodone pills would need to be transported and stored more securely and traffickers would be subject to increased criminal penalties, according to a news release from Manchin's office.

Sen. Jay Rockefeller, D-W.Va., and three other senators -- including two other Democrats and a Republican -- co-sponsored the amendment.

"I'm truly pleased that this amendment has passed and will make it much harder for anyone to abuse these prescription drugs," Manchin said in a statement. "I offered this legislation on behalf of the countless West Virginians whose lives have been cut short by drug abuse and the families who are picking up the pieces.

"I'm committed to working extremely hard across the aisle to see this most important legislation passed," he said.

Prescription drugs are responsible for about 90 percent of all drug-related deaths in West Virginia, and about 75 percent in the U.S, according to Manchin's release.

Schedule I drugs contain the most dangerous substances. Currently, hydrocodone is considered a Schedule II drug, but when combined with substances like Tylenol, they are listed in a less stringent category, Schedule III.

The amendment would make all substances containing hydrocodone Schedule II drugs.

Findings show that more than 40 people die every day from overdoses involving narcotic pain relievers like hydrocodone, methadone, oxycodone and oxymorphone.

"Prescription drug abuse is a very real epidemic that we must stop," Rockefeller said in a statement. "Too many West Virginia families and communities have been hurt terribly, and I've been fighting to turn the tide on abuse."

In addition to co-sponsoring Manchin's amendment, Rockefeller introduced a provision to the FDA reauthorization bill that helps to ensure that doctors, nurses and health-care professionals who prescribe painkillers "get the training they need so they don't overprescribe drugs and can reduce the potential for patient abuse," according to a news release from Rockefeller's office.

Rockefeller's provision would require the Institute of Medicine to study the scope and scale of education requirements for physicians and other people who prescribe medicine. The Institute of Medicine is an independent agency of medical and public health experts who advise Congress on medical and health issues.

Rockefeller also offered an amendment to help support state prescription drug monitoring programs.