Can you take ibuprofen if you take 0.5 mg of lorazepam?

Well, I just did. I'll let you know if I survive. (Not a joke). In all likelihood, low doses of both should be okay. ibuprofen is a pain reliever and reduces inflammation. Pain relieves are not good to take with benzodiazepams because the benzo is going to suppress nervous system activity while the pain reliever will intensify the effect.

Too much of an NSAID like ibuprofen can cause reduced nervous system reaction as well. Combined with Ativan (lorazepam), too much can make you fall asleep and way too much may stop nervous system functions, like your heart...

Low doses of both though, (200 mg of ibuprofen with 1 mg of lorazepam) will be fine... however, you shouldn't really need to take both. Take a different pain med for pain, not an NSAID. Tylenol might be better, but I'm not a doctor. There are likely side effects or consequences for everything.

General rule of thumb - unless told by a doctor - don't mix medications too much, even over the counter ones with prescription meds.