Two cases involving five major U.S. retail pharmacy chains winding their way through court foretell a long and costly road ahead for all companies across the pharmaceutical supply chain battling litigation for their alleged roles in fueling the nationwide opioid epidemic.

In total, more than 3,000 opioid-related cases have been filed in state and federal courts over claims broadly alleging both the actions and nonactions of drugmakers, drug distributors, and pharmacy chains “led to a severe oversupply of prescription opioids, which ultimately created a public nuisance,” according to court documents. Judge Dan Polster of the U.S. District Court for the Northern District of Ohio is presiding over the now coordinated multidistrict opioid litigation.

The consolidated cases in this first wave of litigation are called “bellwether” trials because each represent test cases for opioid-related litigation to come. Unlike some major drugmakers and drug distribution companies, no retail pharmacy chain has yet reached a nationwide opioid-related agreement.