Arkansas is suing Minnesota-based Optum Inc. and another pharmacy benefits manager, Express Scripts, accusing them of fueling the opioid crisis.

Court documents describe "the misuse, abuse, diversion and over-prescription of opioids" as "the worst man-made epidemic in modern medical history."

Arkansas Attorney General Tim Griffin said the companies, which run prescription drug coverage for insurers, should be held accountable "for their roles in a crisis that has ravaged our state."

"The [companies] benefited financially from the opioid crisis in Arkansas by negotiating favorable deals with opioid manufacturers," Griffin said in a news release.

Optum, a subsidiary of UnitedHealth Group, denies the claims.

"Optum did not cause the opioid crisis or make it worse, and we will defend ourselves in this litigation," the company said in a statement. "Optum takes the opioid epidemic seriously and has taken a comprehensive approach to fight this issue, including the Opioid Risk Management Program available to all Optum Rx clients, to address opioid abuse and promote patient health."

Arkansas had the second-highest opioid prescription rate in the nation for many years, according to the suit, and it remained the most commonly prescribed controlled substance as recently as 2022.

Pharmacy benefit managers "sit at the center of prescription-drug dispensing" and intentionally caused an oversupply of opioids in the state, the suit says.

The lawsuit accuses Optum and Cigna-owned Express Scripts of "colluding with Purdue Pharma and other opioid manufacturers to increase opioid sales through favorable placement on national formularies in exchange for rebates and fees."

Formularies are lists of drugs covered by insurance plans.

The state is seeking unspecified damages and restitution for claims of creating a public nuisance, negligence and unjust enrichment.