Learn your insulins: Humulin, HumuLOG, 70/30, Lantus, etc. GOD HELP YOU if you screw these up. Forget "mixing" that they taught in school; shoot 'em separate (safer that way). Don't forget the oral antiglycemics like altace and gliburide and glipizide.
Learn the IV ABX: Levaquin, Ancef (kefzol), Zosyn, Vanco
ALL of my pts have been on one or more antihypertensives: Lopressor, Norvasc, atenolol, enalipril, hydralazine, clonipin; more than a few have been on lipitor, zocor, lopid, and/or zetia.
Digoxin, levothroid, protonix, and all the pain meds - morphine, demerol, dilaudid, oxycodone, hydrocodone, and codeine.
Find the old patch before applying a new one. DON'T handle nitropaste w/o gloves (you'll be sorry if you don't). Be double-darned careful when administering blood products.
The most important thing to remember beyond the 5 rights is when NOT to give a med; like dig w/ a HR < 60 or an antihypertensive with a SBP < 100