i have never seen our pt's get two ultrams at once, but if they are just the 50mg plain tabs, i have seen younger patients get it. ultram is one of those funny meds...either it wacks someone out, or it works pretty good. what kind of sleeper are they getting? restoril, ambien? ambien is hands down the most popular at my NH.
ativan and percocet is fine together as well.
what you want to watch for is for people who have impaired liver or renal systems...sometimes these pts need a lower dose. and many older people do have impaired renal/liver systems. you'll see in any drug guide the excretion route of a med, if it's renal it will even have the normal doses.
being a new nurse, i would get to know the "normal ranges/doses" of the meds you give. yes, it takes a good many months, but you will start to remember them over time. every specialty has meds that are commonly used.
as long as those meds you are questioning are not written "not to be given with x" you should be fine. just monitor them for lethargy, etc, esp if it's a new med order for them. that's why it's so important to document your PRN meds, so if the person is excessively groggy the next day, day nurse can look at what the person got last night and see "oh, this person had a PRN ativan.." or any other med. very important.
but, i have given all those meds above together, sometimes more! one lady had 2mg ativan (unusual dose), 10mg ambien, and she got two lortab 10/500's. hardly touched her. but some little old ladies may get 0.5mg of ativan and be asleep for 12 hours....everybody is so different, that's why its so important for the nurse to watch carefully for the effects of any meds!!
good luck, and congrats on being a new nurse!!!