STILLWATER — A Newport woman has pleaded guilty to third-degree murder for giving methadone to her husband to help him sleep.

Jennifer Johnson changed her plea Monday in Washington County court after pleading not guilty less than a month earlier. The 43-year-old was charged in the death of 32-year-old Denis Parmuat in March 2013. Her sentencing is set for December.

Johnson and her daughter told police that Parmuat got home from work and drank about 12 beers. Johnson said he asked for some of her prescription liquid methadone. She said she put about 30-40 milliliters in a syringe and gave it to him.

Officers found him gasping for breath in a bedroom. He was taken to a St. Paul hospital, where he died.

An autopsy showed he died from mixed drug toxicity.