My experience with Rx was pretty ridiculous. I ended up doing the whole bank before pharm started, so I would always uncheck pharm. One of the first blocks I did there was 37 pharm questions on that block.
I mean, it's not like the question was pharm related, by their own metric they were pharm questions. I really hate Rx and the whole first aid empire. So much.
Anyway in my opinion annotating Rx is a giant waste of time. Just read the chapter and do the questions.