What is the solution for Fajr prayer in the event of taking addiction medication that causes deep sleep, and is a person considered sinful if they miss the prayer because of that?

If you repented of your sin and then slept, you must take measures to wake up, such as setting an alarm or appointing someone to wake you. If you do not wake up, there is no sin upon you, and pray when you do wake up, because the Prophet, peace and blessings be upon him, said: "There is no negligence in sleep; negligence is only upon one who leaves a prayer until the time of the next prayer enters."