Study	Reason for exclusion
Altier 2001	Case study
Altier 2005	No comparator group
Arnaert 2006	Patient interview with no pain outcome
Arner 1988	Only one participant received methadone
Beaver 1967	Cancer patients
Bendiksen 2007	No comparator group
Berken 1982	Case study
Bouckoms 1992	Only 7 participants received methadone
Byas‐Smith 2005	Various opioids administered ‐ methadone data not presented separately
Byrne 2001	Letter to editor with no subject data
Cruciani 2005	No comparator group
Flavell Matts 1964	Mixed population ‐ only nine participants in methadone group had chronic non‐cancer pain
Fowle 1978	Letter to the editor with no subject data
France 1984	Only four participants received methadone
Fredheim 2006	No comparator group
Fredheim 2007	No pain outcome
Gagnon 2003	No comparator group
Gallagher 2007	Only three participants received methadone
Gardner‐Nix 1996	Only five participants received methadone
Green 1996	No comparator group
Haythornthwaite 1998	Various opioids administered ‐ methadone data not presented separately
Krebs 2011	No pain outcome
Lockwood 2004	Letter to the editor with no subject data
Manchikanti 2005	No pain outcome
Manchikanti 2009	No pain outcome
McNulty 2000	Data not provided
Mironer 1999	No comparator group
Morley 1993	Only five participants received methadone
Moulin 2005	No comparator group
Naliboff 2011	Various opioids administered ‐ methadone data not presented separately
Peng 2008	No comparator group
Robbins 1996	No comparator group
Robbins 1997	No comparator group
Robbins 1999	Various opioids administered ‐ methadone data not presented separately
Robbins 2009	No comparator group
Rothrock 1999	No comparator group
Saper 2004	No comparator group
Schofferman 1999	Only 8 participants received methadone
Shir 2001	No comparator group
Sjøgren 2000	No pain outcome
Sprenger 2008	Case study
Taylor 2000	No pain outcome
Urban 1986	No comparator group
Walmsley 2010	No comparator group
Watson 2010	Various opioids administered ‐ methadone data not presented separately
Webster 2008	No pain outcome