AUTHOR=Zandonai Thomas , Escorial Mónica , Peiró Ana M. TITLE=Codeine and Tramadol Use in Athletes: A Potential for Abuse JOURNAL=Frontiers in Pharmacology VOLUME=12 YEAR=2021 URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2021.661781 DOI=10.3389/fphar.2021.661781 ISSN=1663-9812