Paxlovid, Drug Exposure

One of several codesets in the PEDSnet `observation_derivation_recover`(ODR) workflow to extract COVID-19 patients from the [PEDSnet CDM](https://hdl.handle.net/20.500.14642/749.12) `observation` table. This concept set was used to identify pediatric patients under 18 who were prescribed Paxlovid. The concept set was developed by identifying RxNorm codes at the SCDF/SCDG level and descendants indicating Paxlovid, then string searching for the terms 'paxlovid', 'ritonavir', and 'nirmatrelvir' in ‘concept_name’. Codes were identified in the ‘code_type’ column as 'Paxlovid' (indicating nirmatrelvir/ritonavir), 'nirmatrelvir' (indicating nirmatrelvir alone) and 'ritonavir' (indicating ritonavir alone). Please note, this concept set should not be used without appropriate accompanying logic to identify Paxlovid; the concept set contains individual ingredients that comprise the combination. Ritonavir and nirmatrelvir exposure must occur together on the same date to indicate a combination drug prescription. The attached file, FIND_PAXLOVID_FUNCITON.R, provides logic showing how the concept set can be used.