Displaying Drug Classes in RxNav.

Linking RxNorm drugs to classes For MeSH, we extracted the PA relations from the MeSH data set and integrated them with RxNorm, in which the MeSH ingredients are already contained. There are 2,533 RxNorm ingredients with a PA relation. For ATC, we created a mapping at the ingredient level between ATC 5-level drugs and RxNorm. There are 2,441 RxNorm (salt or non-salt) ingredients (IN/PIN) with a mapping to ATC.