Some state attorneys general and opioid addiction activists pushed back Tuesday against a settlement offer from OxyContin maker Purdue Pharma, saying it didn't include enough money and goes too far in protecting the company and family members who own it from future liability.

A group of nearly half the state attorneys general said it was disappointed in the plan Purdue filed late Monday night in federal bankruptcy court and some said they would seek changes. The lukewarm reaction from them and others raised doubts about how soon the company could emerge from bankruptcy and begin to compensate...