EFNS guidelines on pharmacological treatment of neuropathic pain

Abstract

Neuropathic pain treatment remains unsatisfactory despite a substantial increase in the number of trials. This EFNS Task Force aimed at evaluating the existing evidence about the pharmacological treatment of neuropathic pain. Studies were identified using first the Cochrane Database then Medline. Trials were classified according to the aetiological condition. All class I and II controlled trials (according to EFNS classification of evidence) were assessed, but lower-class studies were considered in conditions that had no top level studies. Only treatments feasible in an outpatient setting were evaluated. Effects on pain symptoms/signs, quality of life and comorbidities were particularly searched for. Most of the randomized controlled trials included patients with postherpetic neuralgia (PHN) and painful polyneuropathies (PPN) mainly caused by diabetes. These trials provide level A evidence for the efficacy of tricyclic antidepressants, gabapentin, pregabalin and opioids, with a large number of class I trials, followed by topical lidocaine (in PHN) and the newer antidepressants venlafaxine and duloxetine (in PPN). A small number of controlled trials were performed in central pain, trigeminal neuralgia, other peripheral neuropathic pain states and multipleaetiology neuropathic pains. The main peripheral pain conditions respond similarly well to tricyclic antidepressants, gabapentin, and pregabalin, but some conditions, such as HIV-associated polyneuropathy, are more refractory. There are too few studies on central pain, combination therapy, and head-to-head comparison. For future trials, we recommend to assess quality of life and pain symptoms or signs with standardized tools. Background and objectives

Neuropathic pain: Are there distinct subtypes depending on the aetiology or anatomical lesion?

“…Conversely the topical agent capsaicin is effective for PHN, but has been reported to have minimal effect for painful polyneuropathies (1,14). Our data challenge the relevance of using PHN as a model of neuropathic pain in pharmacological studies.…”

“…These analyses indicated that idiopathic trigeminal neuralgia was strongly associated with electric shocks only. From a therapeutic perspective, only trigeminal neuralgia responds particularly well to sodium channel blockers, including carbamazepine, oxcarbazepine and lamotrigine (1,25), which are more modestly effective for other neuropathic pain (1,5,36). Our data emphasize the relevance of distinct definitions, diagnostic and therapeutic algorithms for neuropathic pain and idiopathic trigeminal neuralgia (1, 35).…”

“…From a therapeutic perspective, our findings suggest that the current way of selecting patients on the basis of the disease or topography of the lesion might not be the most appropriate or rational approach (19). This is illustrated by pharmacological trials showing similar efficacy of most treatments of neuropathic pain due to various aetiologies, including painful polyneuropathies and central pain (1,11,14). The multidimensional nature of neuropathic symptoms supports the relevance of subgrouping patients on the basis of symptoms or dimensions in therapeutic trials.…”

“…Previous psychophysical studies have also reported brush-evoked allodynia in 78 to 100% of patients (24,26,31). From a therapeutic perspective, the response of PHN to the major drugs used for neuropathic pain -including gabapentin, pregabalin, tricyclics and opioids -does not seem specific (1,14). However, this condition has particular symptomatic characteristics that may account, in part, for its response to treatment.…”

“…In particular, identification of subsyndromes corresponding to various combinations of symptoms (related or not to the aetiology) may contribute to reformation of current therapeutic strategies (7,8,19). The traditional aetiology-based categorisation of neuropathic pain still prevails for clinical, experimental (20,21) and pharmacological studies (1,11,14). Pharmacological studies have evaluated neuropathic pain as a global and uniform symptom.…”