A woman whose toddler died after taking a fatal dose of a powerful drug was sentenced Monday to 10½ years in prison.

Donna Rose Smith pleaded guilty to manslaughter in connection with her 18-month-old son Patrick’s death in February 2012.

She had been accused of first-degree murder and child abuse.

Police and court documents show the child died from a methadone overdose. Smith 23, was taking the drug to treat her heroin addiction.

“Throughout this case, there really hasn’t been any acceptance of responsibility,” Deputy Pima County Attorney Ryan Schmidt said.

Schmidt also said Smith’s story that her son accidentally ingested methadone mixed with water that spilled on the carpet was inconsistent with the facts.

Court documents show Smith made contradictory statements to Oro Valley police in interviews following the toddler’s death.

She initially told police she gave Patrick Tylenol the afternoon that he died. Smith said she found the child cold and not breathing several hours later.

Days later, however, Smith told police she had spilled her methadone the day before her son died but was uncertain if the boy came into contact with the drug.

She said her son slept normally that night and she gave him a dose of Tylenol in the morning.

Schmidt said the area of the carpet where Smith said she spilled the methadone was tested but no trace of the drug was found. Traces of methadone were found in a child’s Tylenol dispenser.

In addition, Schmidt disputed Smiths’ timeline of the child’s death. He said if the toddler had taken methadone on Saturday, as Smith has said, toxicologists say the child would have died that day, not the following day.

Smith’s attorney, Brick Storts, disputed the characterizations but said he was not defending Smith when the plea deal was agreed to or when a presentence report was written.

Strorts did say any punishment the court handed down would not equal the lifetime of regret Smith would feel.

Smith was the subject of a Child Protective Services investigation after her son’s birth, as the boy was found to have opiates in his blood when born.

Smith told investigators she had taken a painkiller with codeine during her pregnancy and to combat labor pains.

In addition to the prison term, Smith was sentenced to seven years’ probation for a fraudulent schemes and artifices conviction.

Contact reporter Patrick McNamara at 573-4241 or pmcnamara@tucson.com. On Twitter @pm929.