TMZ: Source says Demi Lovato OD didn't involve heroin, but she was revived with Narcan

LOS ANGELES -- Demi Lovato did not overdose on heroin, according to a source connected to the singer, TMZ is reporting. The source would not say what drug caused the OD, but TMZ reported she was given Narcan, which is used to counter the effects of opioids.

Lovato was rushed to an L.A. hospital Tuesday, July 24.

TMZ's sources said Lovato was transported from a home in Hollywood Hills just before noon. Her condition is unknown. TMZ says she was treated with Narcan at her home. In an update, TMZ said Lovato was found unconscious when paramedics arrived.

Lovato was out on Monday night celebrating a friend's birthday in West Hollywood, and TMZ was told she posted photos on her private Instagram of herself and others in the group, and she seemed happy in the photos.

TMZ notes that Lovato has fought substance abuse for years. At one point she lived in a sober living home after getting released from a treatment center. She had been six years sober from alcohol, cocaine and Oxycontin.

In June, she released a song called "Sober" where she revealed she had fallen off the wagon.