Correspondence (letter to the editor): Lack of Differentiation

In this review, a universal recommendation on the use and dosage of tricyclic antidepressants to treat neuropathic pain is provided without taking into account potential differences between the various agents in the group of antidepressant drugs in respect to their efficacy and tolerability for this indication (1). Of the 8 tricyclic antidepressants approved in Germany for the treatment of depressive disorders, only amitriptyline, clomipramine and imipramine are approved for long-term pain treatment as part of an overall therapeutic concept (2). However, in this paper it appears as if all tricyclic antidepressants were equally recommended for the treatment of neuropathic pain. Presumably, the available evidence does not support this view. Furthermore, manufactures’ recommendations vary widely in respect to the recommended dosage (for example, tianeptine 12.5 mg t.i.d. versus amitriptyline 150 mg daily); thus, it is difficult to understand how there could be a uniform dosage recommendation for the indication “neuropathic pain”.

Recommending duloxetine for the treatment of neuropathic pain under the heading “Selective Serotonin-Norepinephrine Reuptake Inhibitors (SSNRIs)“ could create the impression that essentially all SSNRIs are effective in treating neuropathic pain. Even though the authors point out that in Germany venlafaxine is not approved for pain therapy, they do not comment on the third SSNRI approved in Germany for the treatment of depressive disorders, milnacipran. Furthermore, they do not mention that in Germany only Cymbalta and Ariclaim, but not Yentreve are approved for the treatment of pain in patients with diabetic polyneuropathy, even though the active ingredient in all of these products is the same (duloxetine). Prescribing Yentreve for pain therapy or Ariclaim and Cymbalta for the treatment of pain syndromes other than diabetic polyneuropathy is considered “off-label” use of these products.