Schwenkreis 2003.

Study characteristics
Methods	Randomised, DB, parallel, computer‐generated randomisation by doctor not involved in study Ff‐up at end of treatment at 21 days
Participants	Chronic PLP of at least 12 months; traumatic upper limb amputations; 16 participants, 14 males; median age 62 (35 to 71)
Interventions	memantine titrated up to 30 mg/day x 3 weeks placebo
Outcomes	Pain intensity; Dropouts/withdrawals; Other outcomes: intracortical inhibition; intracortical facilitation
Notes	Small number of participants; n = 16
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated randomisation
Allocation concealment (selection bias)	Low risk	Doctor not involved in study performed randomisation; hospital pharmacy prepared medication
Blinding (performance bias and detection bias) All outcomes	Low risk	"the study medication was produced in hospital pharmacy using capsules of same colour and size for placebo and memantine"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	The investigator who undertook the TMS and data analysis was blinded to participants' treatment allocation and assessed pain intensity at same time
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	1 participant in memantine group who did not continue with drug due to adverse events was excluded from study and not included in analysis
Selective reporting (reporting bias)	Low risk	All specified outcomes in methods section of published study were reported, although not necessarily as our preferred outcomes
Other bias	Low risk	Baseline characteristics between 2 groups similar
Size of study	High risk	n = 16