title: Authors' reply.
authors.affiliation: University of California (UC), San Diego, Skaggs School of Pharmacy and Pharmaceutical Sciences, La Jolla, CA, USA.
authors.forename: Natalie M
authors.initials: NM
authors.lastname: Elder
authors.affiliation: University of California (UC), San Diego, Skaggs School of Pharmacy and Pharmaceutical Sciences, La Jolla, CA, USA Doris A. Howell Pain and Palliative Care Service, La Jolla, CA, USA.
authors.forename: Rabia S
authors.initials: RS
authors.lastname: Atayee
authors.affiliation: University of California (UC), San Diego, Skaggs School of Pharmacy and Pharmaceutical Sciences, La Jolla, CA, USA UC San Diego Department of Pediatrics, Rady Children's Hospital, San Diego, CA, USA brookie@ucsd.edu.
authors.forename: Brookie M
authors.initials: BM
authors.lastname: Best
authors.affiliation: University of California (UC), San Diego, Skaggs School of Pharmacy and Pharmaceutical Sciences, La Jolla, CA, USA Doris A. Howell Pain and Palliative Care Service, La Jolla, CA, USA.
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Ma
mesh_terms: D000701:Analgesics, Opioid / Q000652:urine*; D005260:Female; D006801:Humans; D008297:Male; D009019:Morphinans / Q000652:urine*; D010098:Oxycodone / Q000652:urine*; D010111:Oxymorphone / Q000652:urine*; D010146:Pain / Q000188:drug therapy*
chemical_list: D000701:Analgesics, Opioid; D009019:Morphinans; D010111:Oxymorphone; D010098:Oxycodone