If you're going in for neurosurgery, do you want a neurosurgeon who knows every nook and cranny of the brain with their eyes closed? Or are you fine with a high school student who is Googling everything as he's cutting through your brain?
From your profile, it looks like you are trying to apply to a Pharm.D. program. If I were on the admissions committee and knew that you asked this question, I would get your application thrown out. Seriously, it's an essential part of your job. Yes, there are references available, but you need to have a working knowledge of interactions in order to function as a pharmacist.