During our antibiotics teaching at medical school we were told that a recent survey of junior doctors had revealed that a significant proportion didn't realise that augmentin, tazocin, and carbopenems were penicillins and as such should not be given to those with known allergies. I devised a "mind-map" summarising the main antibiotics in use using information from the BNF and my own lecture notes. For me, seeing the information laid out in this manner, pinned above my desk as I work, helps me remember the major classes, their relationships with one another, and their major side-effects.
