Open Question: What happens if you take 1 sleeping pill when your 13?

My 13 year old sister has a very bad cold and has trouble sleeping. She had mild insomnia before, like could not fall asleep till 1am. She's not "small" as in a little kid, she's adult-size and she has no allergies or mental or physical problems. She's not taking other meds except iv-profan and strepsils. What would happen if she took 1 sleeping pill? Pretty much, would she die? Or not wake up? Thanks

Tagged as: Adult Size, Allergies, allergy, Insomnia, Little Kid, Meds, Open Question, Profan, Sleeping Pill, Strepsils, Trouble Sleeping