Hampf 1989.

Methods	Parallel study design, five weeks (two weeks dose escalation of amitriptyline, one week of distigmine, thereafter stable dose). Patients were randomly allocated to three treatment groups, in addition fourth group of patients who have already taken amitriptyline were included in the study Patients in group four are excluded from the review as well as patients with low back pain and multiple sclerosis Randomisation methods not stated
Participants	Any neuropathic pain. Duration of symptoms from four months to 13 years. Age range from 30 to 75 years. 65 participants (24 final number). Pain score in amitriptyline group 7.0, in distigmine group 6.8, and in placebo group 7.6
Interventions	Amitriptyline dose escalation from 25 to 75 mg; distigmine from 5 mg to 10 mg; or combination of amitriptyline and distigmine daily orally
Outcomes	Pain intensity measured by VAS VAS on amitriptyline 4.9, on distigmine 4.5 and on combination therapy 4.2
Notes	Dropouts 41/65; 15/65 reason not stated, 14/65 in group four, 12/65 low back pain or multiple sclerosis. Side‐effects not reported QS = 1 (R1, DB0, W0)
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	D ‐ Not used