Major pharmaceutical companies embroiled in a multibillion-dollar opioid trial are pinning blame for rampant abuse of prescription narcotics on fellow drugmaker Purdue Pharma, gambling that they can impugn Purdue's marketing of OxyContin without incriminating their own promotion of painkillers.

Big Pharma's finger-pointing has played out during a momentous trial pitting California municipalities against drugmakers accused of deceiving doctors about addiction risks in much the same way as Purdue, which avoided the trial because of its bankruptcy.

"Let's talk about who Endo is not. Endo was no Purdue — not even close," Hueston Hennigan LLP partner John C. Hueston said in defense of Endo Pharmaceuticals, which has devoted much of its trial time to pummeling Purdue.