Tasmuth 2002.
| Methods | Double‐blind, placebo‐controlled cross‐over trial of 4 weeks (4 weeks' dose titration to maximum tolerated dose). 2 x 4‐week periods with 2‐week washout and no carry over effect | |
| Participants | 15 women with breast cancer of mean age 55 years (range 37 to 72), all with postoperative neuropathic pain. Baseline pain score by VRS (0‐7), median 3 (range 3 to 4) and baseline depression score by BDI (0‐63), median 10 (range 1 to 28). All were recruited in Finland | |
| Interventions | Venlafaxine dose escalation from 18.75 mg/day to 75 mg/day orally or placebo. 11 women used 75 mg/day by end of the study period. Women were not allowed to take any other medication that was significantly metabolised by the cytochrome P450 2D6 isozyme | |
| Outcomes | Participant‐reported pain relief (VRS 0‐4) and pain intensity (VRS 0‐7) were the primary outcome measures and also BDI (0‐63) Median pain relief on venlafaxine 2 (range 0 to 4) and on placebo 0 (range 0 to 4) Pain intensity on venlafaxine 1 (range 0 to 3) and on placebo 2 (range 0 to 4) BDI score on venlafaxine 7 (range 1 to 39) and on placebo 7 (range 1 to 11) |
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| Notes | 2/15 women dropped out, 1 due to adverse effects of venlafaxine (nausea, sweating headache) and 1 due to non‐compliance. Blood sampling confirmed that 2 'poor responders' had low venlafaxine concentrations and were classified as fast hydrolysers. There was a strong placebo effect on pain | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | It is stated that the hospital pharmacy provided the venlafaxine and placebo dosage forms and 'performed the randomization using computer‐generated numbers' |
| Allocation concealment (selection bias) | Low risk | Concealment was performed centrally by the hospital pharmacy |
| Blinding of participants and personnel (performance bias) All outcomes | Unclear risk | Double‐blinding was mentioned but details were not provided |
| Blinding of outcome assessment (detection bias) All outcomes | Unclear risk | It was mentioned that the researcher who interviewed the women was not part of the clinical team. No other details were provided |
| Incomplete outcome data (attrition bias) All outcomes | High risk | > 10% of women did not complete the trial and completer analysis was employed |
| Size | High risk | < 50 participants per treatment arm |