Epocrates

The free version of this app features a drug reference, interaction checker, pill identifier, clinical calculators, and a list of "tables" which provide some useful comparisons, such as corticosteroid equivalents, and references such as the Beers Criteria. The drug reference is easy to use, but does not include a lot of detail. Its best uses probably include a quick dosage or interaction check, or for quickly identifying a loose pill. The upgraded version includes information on disease states and lab results. 

Overall Impressions from Around the Web: Generally very positive feedback except for recent problems with Android’s newest version, Ice Cream Sandwich, which one reader complained is making the app "freeze."

Epocrates (iOS)

Epocrates (Android)