Study	Reason for exclusion
Ahlstrom 1989	No placebo control
Apaydin 1994	No placebo control
Aranda 1989	No placebo control
Carlos 1984	Could not be obtained despite attempts to contact authors, ordering through British library and help from librarians at Novartis and Knoll pharmaceuticals
Dorfmann 1991	Inadequate description of method. Did not say whether the allocation was randomised, did not say when interventions were administered, no mention of the level of baseline pain and did not define the pain measurement used
El-Tanany 1993	No placebo control
Fineschi 1997	No placebo control
Frezza 1985	Unobtainable
Garcia 1997	Intravenous route
Graf 2000	Not obtainable
Henderson 1994	No placebo control
Henrikson 1982	Only presented data for the placebo arm for the first hour
Hultin 1978	Cross-over study with the first dose administered exactly one hour after LA rather than when patients experienced moderate to severe pain
Iqbal 1986	Unobtainable
Iwabuchi 1980	No placebo control
Joubert 1977	Unobtainable
Kittala 1972	Routine intervention administration irrespective of baseline pain intensity
Li 1998	No placebo control
Matthews 1984	Intervention administered irrespective of baseline pain intensity
Mayer 1980	Multiple dose study with no mention of baseline pain
Nakanishi 1990	No placebo control
Rautela 1998	Intramuscular route
Shimura 1981	No placebo control
Tam 2001	Intervention administered before procedure
Tani 1974	No placebo control
Tesseroli 1986	At baseline, the mean VAS minus 1.96 × SD was less than 30 mm, therefore some patients may have been included with a baseline pain of less than moderate intensity
Ujpal 1999	No placebo control
Vigneron 1977	Unobtainable
Walton 1993	First dose administered IM during surgery, oral doses then given postoperatively at specified time points irrespective of baseline pain
Wuolijoki 1987	Intervention administered pre-operatively or immediately post-operatively irrespective of baseline pain intensity
Zhang 2000	Could not be obtained