As a student, we weren't really expected to be walking BNFs, more so, we were periodically tested on the major classes of drugs. So, as others have suggested, memorizing the indications/contraindications/side effects/etc. of classes of drugs (rather than individuals) will help. You should also try to align your study method with what helps you learn (e.g. making an online quiz, flashcards, recording and playing back yourself reciting drug information, study groups, roleplaying patient interactions with friends, etc.) Whatever works for you.
Also, for when you are out in the big wide world of Pharmacy, it gets easier. Using this information in a practical sense day-to-day makes it stick far easier than passively reading it out of a textbook.