Tarascon's Pocket Pharmacopoeia and the Sanford Guide are the most lightweight choice I can think of. After the first few hours of rounds, even those little books get annoyingly heavy in yer labcoat. If you pick Tarascon's, you have to know your MOAs cause it's not in the book. For ID, I liked "Antibiotic Essentials" better than Sanford but it is heavier. There are palm versions of the Washington Manual (nice all-around reference) and Hopkin's ABX guide. My rotations were ID, ICU, psych and geriatrics, so these resources did the trick-not sure what you'd need for peds or chemo. Good luck!
