Truthfully, you would probably be safe taking both in conjunction without having to worry about deadly respiratory depression. The respective dosages are low and unless you are extremely sensitive to either drug, you should be fine. If, at any rate you would like to practice optimum HR, I would wait a good hours before dosing the Oxycodone. Lorazepam (Ativan) is considered to be a Benzodiazepine of short(er) duration of effect. If I were advising you on mixing with a Benzo like Clonazepam (Klonopin), I would extent that time-table, as Clonazepam has a significantly longer duration of action.