RT Journal Article SR Electronic T1 Stepping down asthma treatment JF Drug and Therapeutics Bulletin JO Drug Ther Bull FD BMJ Publishing Group Ltd SP dtb-2021-000017 DO 10.1136/dtb.2021.000017 YR 2021 UL http://dtb.bmj.com/content/early/2021/04/12/dtb.2021.000017.abstract AB