I work the night shift and I've heard other nurses say they never give a patient a sleeping pill later in the shift as the morning is approaching... or even 2-3. I say who cares? If it's ambien 5mg q HS prn... does that mean if the patient didn't take it between 8pm-1am then they can't have it at all? Why does it matter when they sleep... it's not like they have to get up at 7am to go to work. They are just sitting in the hospital all day watching TV or talking on the phone... what does it matter when they sleep... if the patient specifically requests a sleeping pill at an odd time, I think it would be appropriate to explain to the patient that it may mess up their sleeping schedule and that they may only have 1 dose in a 24 hour period but if they still want the sleeping pill I don't see how you could tell them no. It's really not my business when they sleep. Is "HS" really a specific time? It stands for within an hour of sleep. I work night shift so my HS is between 10am-12pm. I take my sleeping pill around that time.