Study	Reason for exclusion
Avidsson 1991	Formoterol versus salbutamol ‐ no theophylline arm
Barnes 1992	Review only
Brogden 1991	Review only
Brogden 1992	Review only
Cheung 1998	Does not compare salmeterol with theophylline
Davies 2000	Review only
Donohue 2001	Review only
Dutta 2002	Review only
Eda 1993	Not a randomised controlled trial
Faulds 1991	Reveiw only
Gokhale 2002	Review only
Hancox 2001	Review only
Holimon 2001	Review only
Hunt 2002	Review only
Kleerup 1997	Review only
Lockey 1999	Compares Salmeterol with placebo, no theophylline arm
Lotvall 1992	Review only
Manchee 1996	Not a randomised controlled trial
Meier 1997	Not a randomised controlled trial
Midgren 1992	Comparing formoterol with salmeterol, no theophylline arm
Morice 1999	Compared short‐acting beta‐agonist with theophylline
Nelson 1996	Review only
Nightingale 1995	Not a randomised controlled trial
Paciorek 1991	Not a randomised controlled trial
Rossi 2002	Randomised controlled trial in patients with COPD
Skloot 2002	Review only
Taburet 1994	Review only
Taccola 1999	Randomised controlled trial in patients with COPD
Thomson 1998	Review only
Tomac 1996	Controlled clinical trial ‐ Not a randomised controlled trial
Vatrella 2005	Single dose pharmacokinetic, crossover study. No measurable outcome.
Weinstein 1997	No theophylline arm