Impact of antidepressant medication on the analgetic effect of repetitive transcranial magnetic stimulation treatment of neuropathic pain. Preliminary findings from a registry study.

OBJECTIVES: Repetitive transcranial magnetic stimulation (rTMS) has been found to be effective in chronic neuropathic pain conditions. However, information about the combined effects of rTMS and antidepressant treatment is scarce. We studied the outcome of rTMS and concurrent antidepressant treatment in patients with neuropathic pain. METHODS: In this retrospective, real-world study, 34 patients with neuropathic pain, who were considered resistant or not benefitting from conventional treatment, received rTMS treatment between 2017 and 2020. Pain-related factors were measured using the Numerical Rating Scale (NRS), Global Impression of Change (GIC), and Beck Depression Inventory. RESULTS: A decrease in pain intensity and pain interference assessed with NRS was observed after 10 treatment sessions in 16 patients. The impression of change was positive in 20 patients. Half of the patients (n=17) used antidepressant medication, while half (n=17) did not. A concurrent use of antidepressants with therapeutic rTMS was significantly linked with less pain intensity relief when compared with the nonuse of antidepressants (p=0.019). The impression of change was significantly in favor of the antidepressant nonuser group (p=0.002). No group differences in pain interference were found between the groups. CONCLUSIONS: Therapeutic rTMS for neuropathic pain is plausibly sensitive to interference with antidepressant medication. The exact mechanism of our findings remains to be elucidated; confirmatory studies are warranted.