Kishore‐Kumar 1990.

Methods	Double blind placebo controlled crossover design, six weeks. Two six weeks treatment periods (four weeks titration to max dose then two weeks stable dose), no washout. No carry over effect Randomisation method not stated Inclusion criteria: duration of symptoms at least three months
Participants	Postherpetic neuralgia of 28.5 months (3 months to 8 years). 26 participants (19 final number). Mean age 62 years (range 38 to 79 years), 17 male and 9 female patients
Interventions	Desipramine dose escalation 12.5 mg to 250 mg daily orally, mean dose 167 mg (13 mg); or active placebo (benzatropine 0.5 mg to 1 mg and lactose) daily orally (19 patients took 1 mg, 3 patients 0.5 mg)
Outcomes	Pain patients reported, 6‐item global improvement At least moderate improvement 12/19 on desipramine (complete improvement 1, a lot 7, moderate 4, slight 2, no change 4, worse one), 2/19 on placebo (complete improvement 0, a lot 1, moderate 1, slight 0, no change 9, worse 8)
Notes	Dropouts 7/26 (SE or intercurrent medical illnesses) SE 19/19 on desipramine, 15/19 on placebo. Withdrawn due to SE 5/19 on desipramine (1 syncope, 1 palpitation and left bundle branch block, 1 chest pain, 1 fever, 1 vertigo); 3/19 on placebo (1 vertigo and nausea, 1one skin rash, 1 feeling of unsteadiness) Pain results illustrated only in figures QS = 3 (R1, DB1, W1)
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	B ‐ Unclear