Updated

The U.S. government is tightening restrictions on hydrocodone, an opioid painkiller contained in Vicodin and other addictive drugs.

The move comes as health and law enforcement officials try to curb a rising tide of prescription drug abuse. Nearly three out of four prescription drug overdoses are caused by opioid painkillers, according to federal data.

"Almost seven million Americans abuse controlled-substance prescription medications, including opioid painkillers, resulting in more deaths from prescription drug overdoses than auto accidents," DEA Administrator Michele Leonhart said in a statement announcing the move on Thursday.

In the future, products such as Vicodin that combine hydrocodone with another substance such as acetaminophen or aspirin, will be classed as Schedule II products, in line with the opioids oxycodone and morphine.

Reclassifying the products will make them harder to obtain, both by addicts and legitimate pain patients. Physicians will not be allowed to call in a prescription to a pharmacy. Patients will have to present a written prescription.

Also, fewer refills will be allowed before patients must return to see their doctor. Opponents of the reclassification, which has been in the works for several years, argue that restricting pain products could cause hardship to patients with chronic illnesses, especially the elderly.

Hydrocodone itself has been a Schedule II drug for decades, but combination products have had a less restrictive Schedule III designation. The DEA said that products that combine hydrocodone with another drug - acetaminophen in the case of Vicodin - are still highly addictive.

"Today's action recognizes that these products are some of the most addictive and potentially dangerous prescription medications available," Leonhart said.

Vicodin is made by AbbVie. Other brand names containing hydrocodone in combination with another drug include Lortab, made by UCB.