Law enforcement officials told TMZ that paramedics tended to Curtis' call at 9 p.m. in Venice, Calif. and found her friend unconscious in the backseat of the car.
Sources claim the actress' friend suffered from an explosive reaction after mixing alcohol with prescription medication.
The True Lies star reportedly tried to drive her friend to the hospital herself, but decided to call 911 instead as her condition worsened.
Paramedics drove the friend to the hospital where she was treated and released hours later.
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