WASHINGTON — The maker of OxyContin said it has completed testing of an abuse-resistant version of the painkiller hydrocodone, a surprise development that could derail sales of the recently launched Zohydro, a similar medication that has been criticized for lacking such safeguards.
Purdue Pharma said it plans to submit its extended-release hydrocodone drug to the Food and Drug Administration later this year. The tablets are designed to prevent users from crushing them for snorting or injection.
Shares of rival Zogenix Inc. plunged more than 20 percent after the announcement, which appears to jeopardize sales of the company’s Zohydro. Physicians would presumably be more likely to prescribe a harder-to-abuse form of hydrocodone to try to protect their patients from addiction and abuse. And the Food and Drug Administration could potentially pull Zogenix’s drug off the market if its regulators determine that a safer alternative is available.
Zogenix began shipping Zohydro to pharmacies last week.
Purdue Pharma said a study of its once-a-day hydrocodone pill showed positive results in a 588-patient study of low back pain. Sixty-five percent of patients experienced at least a 30 percent reduction in their pain, while 48 percent reported a 50 percent reduction in pain, according to the company. Purdue Pharma’s formulation would last longer than Zohydro, which is designed to be taken twice a day. Pain experts said both durations are important for treating different types of conditions and patients.
‘‘As a pain specialist, and specifically a cancer pain specialist, I think we are always interested in adding more tools to our toolbox,’’ said Larry Driver, a professor at the MD Anderson Cancer Center in Houston. It boils down to individualizing patient care to prescribe the safest and most effective regimen available.’’
However, patient safety advocates said Wednesday there are already too many prescription narcotics available.