CHARLESTON, W.Va. — The Mingo County Commission and the Town of Kermit have filed a proposed class action federal lawsuit against a management consulting firm which helped Purdue Pharma triple sales of OxyContin, after the drug company had pleaded guilty to improperly marketing the drug.

Purdue Pharma pleaded guilty to misbranding OxyContin in 2007 and entered into a “corporate integrity agreement” intended to more strictly govern the company’s sales and marketing of the drug.

At the same time, the lawsuit alleges the Sackler family sought to increase sales in order to make the company more attractive to a buyer, and they hired McKinsey and Company to help achieve that goal.

“In short, the Sacklers planned to engage in a final flurry of opioid pushing in order to rid themselves of their pharmaceutical company dependency for good,” the complaint reads.

Mingo County and Kermit maintain that OxyContin sales should have gone down by stamping out improper use of the drug. Instead, the complaint says McKinsey “turbocharged” marketing of the dangerous and addictive drug, tripling sales within five years.

McKinsey did this by convincing Purdue Pharma to market OxyContin as “hope in a bottle,” to sell higher doses of the drug, and to target existing high prescribers for additional marketing.

McKinsey has since stopped doing business with any opioid maker and issued a statement in December saying its work on marketing OxyContin fell short of its corporate responsibility.

Kermit and Mingo County are suing McKinsey for negligence, negligent misrepresentation, conspiracy, fraud and unjust enrichment. They are seeking reimbursement for past and future medical, drug treatment and law enforcement costs, as well as punitive damages.