Normalizes drug mentions extracted by OpenMed to RxNorm RxCUIs using the free public RxNav/RxNorm REST API. Use when the user wants to code, standardize, or de-duplicate medication names, resolve a brand/generic/ingredient to a stable RxCUI, link strength+dose-form to an SCD/SBD, attach NDCs, or build a US Core Medication resource. Trigger keywords: RxNorm, RxCUI, RxNav, drug normalization, medication coding, NDC, ingredient, SCD, SBD, brand vs generic, getApproximateMatch. Pairs after OpenMed NER: consume Pharmaceutical/Chemical entities from openmed.analyze_text and map each drug span to an RxCUI. RxNorm and RxNav are fully public and free — no API key, no license barrier, the lowest-friction terminology in this set.