[CHICAGO] The first civil trial that could hold a drug company responsible for the US opioid epidemic began on Tuesday in Oklahoma - a landmark case that could impact thousands of others like it.

The bench trial pits the state of Oklahoma against Johnson & Johnson. Two other drug companies named in the lawsuit settled ahead of the trial.

Oklahoma has accused the three drug makers of deceptively marketing opioid painkillers, hyping their effectiveness and downplaying the risks of addiction.

The lawsuit is the first of many to go to trial, and is seen as an important test of whether drug companies can be held accountable in court for an addiction epidemic, which has killed tens of thousands of Americans.

In opening statements, Oklahoma Attorney General Mike Hunter accused Johnson & Johnson of being motivated by greed in embarking on "a cynical, deceitful multimillion-dollar brainwashing campaign" to sell opioids as a "magic drug."

"It's time to hold them responsible for their actions," Mr Hunter told the presiding judge, who will decide the case in lieu of a jury.

Johnson & Johnson has denied the charges levied by the state against its subsidiary Janssen Pharmaceuticals.

The company's lead attorney pointed to federal and state agencies having approved and monitored its painkillers Nucynta and Duragesic, and the decades-long familiarity of doctors with opioid medications and their addictive qualities.

"Both pharmacists and physicians have an independent responsibility to prescribe and monitor these drugs," attorney Larry Ottaway said.

He also said that the company's two drugs were prescribed in low quantities in Oklahoma and were deemed by government agencies as "rarely addictive" because of their timed-release mechanisms.

2,000 LAWSUITS 

"Janssen's conduct was not a nuisance," Mr Ottaway added, referring to the state's public nuisance law under which it is being sued.

"They provided medically necessary medications for the treatment of terrible, terrible problems. Those treatments were approved and regulated by the FDA," he said.

Medical professionals were likely to testify for both sides in the trial, which is expected to last two months.

Attorneys said among them will be Russell Portenoy, a once highly-regarded pain expert who spent decades touting the benefits of opioid painkillers and claiming their risks were overstated, before changing his view after numerous lawsuits.

There are some 2,000 lawsuits brought by states, cities and Native American territories across the country, all seeking compensation from makers of the highly addictive prescription painkillers.

The lawsuits are being compared to the 1998 cases against Big Tobacco, which ended in a 46-state overarching settlement estimated at US$250 billion in annual payments over the first 25 years of it being in force.

In the Oklahoma lawsuit, Israeli pharmaceutical giant Teva on Sunday settled the case for US$85 million.

Purdue Pharma, maker of the opioid painkiller OxyContin - a key driver of the crisis - reached a US$270 million settlement with the state in March.

Overdoses from prescription painkillers and heroin exploded over the last 20 years, according to the National Institute on Drug Abuse.

Almost 400,000 people have died from an overdose involving prescription or illicit opioids, according to the Centers for Disease Control and Prevention.

Pop icon Prince and rocker Tom Petty were among the high-profile victims of the epidemic.

AFP