Is it ok to take 1mg of ativan (lorazepam) with 800mg ibuprophen?

Yes, but.... ....if you're taking 800 mg ibuprofen you may only take it every 8 hrs. I suggest you NOT take that high a dose very long. I'm unaware of any adverse reaction between NSAIDs and Ativan (lorazepam); doesn't mean there isn't a some chance. For confirmation, speak with the prescribing physician for the Ativan (lorazepam). Good luck.
Should be ok. Depending on why you're taking both of those medications ... They're not contraindicated with each other & should be okay. Good luck!