Computer-assisted methods and systems of processing a drug information source. Characterizing the drug by the set comprising: syntax-parsed drug rule elements, adverse event data, mapped terms, and metadata. A method includes: creating a drug rule syntax; extracting metadata from the drug information source; extracting verbatim adverse event data from the drug information source; identifying drug rule content from the drug information source; mapping terms from verbatim data to a reference source; and parsing drug rule elements from at least one identified instance of drug rule content into the drug rule syntax, retaining associations between those drug rule elements that form a drug rule.