sdtm_ex.RdExposure data frame - One record per constant dosing interval per subject
sdtm_exa data frame with 591 rows and 17 columns. See https://github.com/SafetyGraphics/safetyData/blob/main/data-raw/sdtm/README.md for more details and full data specification. Columns:
 STUDYID text - Study Identifier
 DOMAIN text - Domain Abbreviation
 USUBJID text - Unique Subject Identifier
 EXSEQ integer - Sequence Number
 EXTRT text - Name of Actual Treatment
 EXDOSE integer - Dose per Administration
 EXDOSU text - Dose Units
 EXDOSFRM text - Dose Form
 EXDOSFRQ text - Dosing Frequency per Interval
 EXROUTE text - Route of Administration
 VISITNUM float - Visit Number
 VISIT text - Visit Name
 VISITDY integer - Planned Study Day of Visit
 EXSTDTC date - Start Date/Time of Treatment
 EXENDTC date - End Date/Time of Treatment
 EXSTDY integer - Study Day of Start of Treatment
 EXENDY integer - Study Day of End of Treatment