Study	Reason for exclusion
Abreu 2006	cross‐over design
ACTRN12608000502336	study of people with stable COPD
Ahmed 2020	study of intraoperative magnesium sulfate infusion in people with stable COPD
Amaral 2012	study in people with stable COPD
CTRI/2018/01/011354 2018	not an RCT
CTRI/2018/04/013309 2018	not an RCT
Fan 2015	study of magnesium sulfate inhalation versus alpha chymotrypsin atomisation inhalation
Friemann 1991	study of magnesium aspartate hydrochloride
ISRCTN65174202 2006	study was stopped due to participant recruitment issues
Jenner 2004	not an RCT
Marino 1999	cross‐over trial
NCT01118936 2010	study in people with stable COPD
NCT02498496 2015	study was withdrawn due to financing delays
NCT02680769 2016	study in people with stable COPD
Schenk 2001	not an RCT
Skorodin 1998	study of magnesium sulfate and ipratropium bromide combination versus salbutamol and normal saline without magnesium sulfate monotherapy arm
Sternfeld 1994	not an RCT
Tagaya 2004	study in people with stable COPD