(Reuters) - New Hampshire sued OxyContin maker Purdue Pharma LP on Tuesday, joining several state and local governments in accusing the drugmaker of engaging in deceptive marketing practices that have helped fuel a national opioid addiction epidemic.

A pharmacist holds prescription painkiller OxyContin, 40mg pills, made by Purdue Pharma L.D. at a local pharmacy, in Provo, Utah, U.S., April 25, 2017. REUTERS/George Frey

The lawsuit filed in Merrimack County Superior Court claimed that Purdue Pharma significantly downplayed the risk of addiction posed by OxyContin and engaged in marketing practices that “opened the floodgates” to opioid use and abuse.

The lawsuit came after the state’s top court in June overturned a ruling that barred the enforcement of subpoenas against Purdue and four other drugmakers because of the use of a private law firm by the office of the attorney general.

The complaint said the Stamford, Connecticut-based company had spent hundreds of millions of dollars since the 1990s on misleading marketing that overstated the benefits of opioids for treating chronic, rather than short-term, pain.

Purdue and three executives in 2007 pleaded guilty to federal charges related to the misbranding of OxyContin, and agreed to pay a total of $634.5 million to resolve a U.S. Justice Department probe.

That year, the privately held company reached a $19.5 million settlement with 26 states and the District of Columbia. It agreed in 2015 to pay $24 million to resolve a lawsuit by Kentucky.

The lawsuit by New Hampshire, which was not among those settled, said Purdue has continued to benefit from its earlier misconduct and has since 2011 expanded the market for opioids in the state.

“New Hampshire continues to experience a severe opioid epidemic,” Deputy Attorney General Ann Rice said in a statement. “Last year alone nearly 500 overdose deaths occurred - almost ten times more than in 2000.”

In a statement, Purdue denied the allegations but said “we share New Hampshire officials’ concerns about the opioid crisis and we are committed to working collaboratively to find solutions.”

According to the U.S. Centers for Disease Control and Prevention, opioids were involved in over 33,000 U.S. deaths in 2015, the latest year for which data is available, and estimates show the death rate has continued rising.

The lawsuit followed similar cases against Purdue and other drugmakers by Oklahoma, Mississippi, Ohio and Missouri and several cities and counties in California, Illinois, Ohio, Oregon, Tennessee and New York.

A group of state attorneys general announced an investigation in June into the role played by pharmaceutical manufacturers in the opioid epidemic.