The United States is facing an epidemic of lethal overdoses from prescription painkillers, which have tripled in the past decade and now account for more deaths than heroin and cocaine combined.

The quantity of painkillers on the market is so high that it would be enough for every American to swallow a standard dose of Vicodin every four hours for one full month, according to the Centers for Disease Control and Prevention.

"The unfortunate and in fact shocking news is that we are in the midst of an epidemic of prescription drug overdose in this country. It is an epidemic but it can be stopped," said CDC chief Thomas Frieden.

"Now the burden of dangerous drugs is being created more by a few irresponsible doctors than by drug pushers on street corners."

The CDC Vital Signs report focused on opioid pain relievers, including oxycodone, methadone and hydrocodone, better known as Vicodin, which have quadrupled in sales to pharmacies, hospitals and doctors' offices since 1999.

Last year, 12 million Americans reported taking prescription painkillers for recreational uses, not because of a medical condition.

The number of deaths from overdoses of opioid pain relievers has more than tripled from 4,000 people in 1999 to 14,800 people in 2008.

The epidemic is at its height among middle-aged white men, age 35-54, and American Indians or Alaska natives, the CDC said.

Rural and poor areas tend to have the highest prescription drug overdose death rates, and the severity of the problem varies widely from state to state.

The drugs are highly addictive and people can build up tolerance quickly, according to Michael Lowenstein, who treats patients at his pain clinic in Los Angeles, California and was not involved with the CDC research.

"What happens in a lot of this population is they take the medication for something like knee pain, or surgery," he told AFP.

"The opiate receptors are very close to the pleasure centers in the brain, so for a period not only does the pain feel better but their anxiety, their depression and their stress is better.

"The problem is it takes more and more medication to maintain that response so someone will be given two or three or four Vicodin to treat their pain and before you know it they are taking 20 and 30 and 40 Vicodin a day."

Death typically occurs when the patient stops breathing because the drugs can cause respiratory depression, and are particularly lethal when mixed with anxiety medications or alcohol.

Lowenstein is co-medical director of the Waismann Method, a $20,000 dollar treatment for opiate dependence that involves sedating the patient for several days in a hospital intensive care unit so that they do not feel the symptoms of withdrawal such as vomiting, nausea and inability to function.

"We can tell what's happening on the street as far as meds and drugs," he added. "When I first started this work 15 years ago, we used to treat a lot of heroin, and now it's been predominantly Vicodin and Oxycontin for years."

The CDC said that deaths and hospitalizations have increased in parallel with the boost in supply, and now deaths from prescription drugs account for almost 75 percent of overdose deaths in which a drug was specified on the death certificate.

The sales rate of the three opioids included in the study reached 7.1 kilograms per 10,000 population last year, or the same as 710 milligrams per person in the United States.

"Enough OPR (opioid pain relievers) were prescribed last year to medicate every American adult with a standard pain treatment dose of five milligrams of hydrocodone (Vicodin and others) taken every four hours for a month," the CDC said.

Even though a relatively small portion of the US population admits abusing prescription painkillers, the costs to health insurance companies are huge -- $72.5 billion per year, according to the report.

States could do a better job of regulating the problem via drug monitoring records and insurance claims information that "can identify and address inappropriate prescribing and use by patients," the report said.

More laws targeting so-called "pill mills," which are prescribing at higher than normal rates in particularly affected states, could also cut back on the problem, it said.