Nobody anywhere in television or movies seems to know the first thing about the drugs they take. I remember the dosages being absurd as well. Also, they used the line "that's 4 times the normal dose!" as if that is supposed to mean anything. What is the "normal dose" of alprazolam, or any drug for that matter? It doesn't exist.
It's a pretty major pet peeve of mine, the inability to do basic research into any of this stuff, and the unintentional spreading of incorrect information that occurs as a result. Don't these people research the drugs they are taking? Isn't there anybody in the writer's room, who has taken Xanax before, and looked at the bottle in order to determine just what dosage they are taking? Does nobody go online to review how the substance they are putting into their body works, and what the potential side effects are?
Sorry for the off topic rant.