I know this post is old but for anyone thinking of it I personally would not. I retook patho (I had taken it several years before, got an A, but my cohort was taking it and I just retook to brush up my knowledge) and took pharm on the same day back to back and it seriously was horrible. I struggled and I had taken patho before, and pharm is probably not as tough as mirco.
You could certainly try but be prepared for a really tough semester. I would advise tutoring and limiting all outside distractions. Let people in your life know you will be mostly unavailable.