TABLE 7.
Average numbers needed to treat (NNT) among placebo-controlled trials examining tricyclic antidepressants (TCAs), and serotonin and noradrenaline reuptake inhibitor antidepressants for neuropathic pain for benefit (50% reduction of pain), and minor and major harm
| Agent (references) | NNT ‘benefit’ | NNT ‘minor harm’ | NNT ‘major harm’* | Number of studies† |
|---|---|---|---|---|
| Amitriptyline (47,51) | 2.4 | 20.4 | 30.5 | 6 |
| Imipramine (47,51,77) | 2.1 | 1.4 | 13.7 | 4 |
| Desipramine (47,51) | 2.4 | 12.4 | 15.2 | 3 |
| Nortriptyline (47,51) | 2.6 | 1.4 | – | 3 |
| Clomipramine (47,51) | 2.1 | no dichotomous data available | 8.7 | 1 |
| Average TCAs | 2.3 | 8.9 | 17 | |
| Venlafaxine (51,76,77) | 4.0 | 2 | ||
| SSRIs (51,88) | 6.7 | 3 |
Major harm consists of withdrawal from the study due to adverse effects;
This column refers to the number of studies for which there was adequate information with which to calculate an average NNT. Please note that these figures derive from studies using different methodologies, different data analyses, with different numbers of patients. There are few comparative trials and the external validity may be poor because of selection that goes into trials. Thus the NNT data is a rough guide only. SSRIs Serotonin-specific reuptake inhibitors