Pharmacological and non-pharmacological treatments for neuropathic pain: Systematic review and French recommendations

Neuropathic pain remains a significant unmet medical need. Several recommendations have recently been proposed concerning pharmacotherapy, neurostimulation techniques and interventional management, but no comprehensive guideline encompassing all these treatments has yet been issued. We performed a systematic review of pharmacotherapy, neurostimulation, surgery, psychotherapies and other types of therapy for peripheral or central neuropathic pain, based on studies published in peer-reviewed journals before January 2018. The main inclusion criteria were chronic neuropathic pain for at least three months, a randomized controlled methodology, at least three weeks of follow-up, at least 10 patients per group, and a double-blind design for drug therapy. Based on the GRADE system, we provide weak-to-strong recommendations for use and proposal as a first-line treatment for SNRIs (duloxetine and venlafaxine), gabapentin and tricyclic antidepressants and, for topical lidocaine and transcutaneous electrical nerve stimulation specifically for peripheral neuropathic pain; a weak recommendation for use and proposal as a second-line treatment for pregabalin, tramadol, combination therapy (antidepressant combined with gabapentinoids), and for high-concentration capsaicin patches and botulinum toxin A specifically for peripheral neuropathic pain; a weak recommendation for use and proposal as a third-line treatment for high-frequency rTMS of the motor cortex, spinal cord stimulation (failed back surgery syndrome and painful diabetic polyneuropathy) and strong opioids (in the absence of an alternative). Psychotherapy (cognitive behavioral therapy and mindfulness) is recommended as a second-line therapy, as an add-on to other therapies. An algorithm encompassing all the recommended treatments is proposed.

Pharmacological and non-pharmacological treatments for neuropathic pain: Systematic review and French recommendations.

Neuropathic pain remains a significant unmet medical need. Several recommendations have recently been proposed concerning pharmacotherapy, neurostimulation techniques and interventional management, but no comprehensive guideline encompassing all these treatments has yet been issued. We performed a systematic review of pharmacotherapy, neurostimulation, surgery, psychotherapies and other types of therapy for peripheral or central neuropathic pain, based on studies published in peer-reviewed journals before January 2018. The main inclusion criteria were chronic neuropathic pain for at least three months, a randomized controlled methodology, at least three weeks of follow-up, at least 10 patients per group, and a double-blind design for drug therapy. Based on the GRADE system, we provide weak-to-strong recommendations for use and proposal as a first-line treatment for SNRIs (duloxetine and venlafaxine), gabapentin and tricyclic antidepressants and, for topical lidocaine and transcutaneous electrical nerve stimulation specifically for peripheral neuropathic pain; a weak recommendation for use and proposal as a second-line treatment for pregabalin, tramadol, combination therapy (antidepressant combined with gabapentinoids), and for high-concentration capsaicin patches and botulinum toxin A specifically for peripheral neuropathic pain; a weak recommendation for use and proposal as a third-line treatment for high-frequency rTMS of the motor cortex, spinal cord stimulation (failed back surgery syndrome and painful diabetic polyneuropathy) and strong opioids (in the absence of an alternative). Psychotherapy (cognitive behavioral therapy and mindfulness) is recommended as a second-line therapy, as an add-on to other therapies. An algorithm encompassing all the recommended treatments is proposed.

Specific impact of stimulant, alcohol and cannabis use disorders on first-episode psychosis: 2-year functional and symptomatic outcomes.

BACKGROUND: Many studies have concluded that cannabis use disorder (CUD) negatively influences outcomes in first-episode psychosis (FEP). However, few have taken into account the impact of concurrent misuse of other substances. METHODS: This 2-year, prospective, longitudinal study of FEP patients, aged between 18 and 30 years, admitted to early intervention programs in Montreal, Quebec, Canada, examined the specific influence of different substance use disorders (SUD) (alcohol, cannabis, cocaine, amphetamines) on service utilization, symptomatic and functional outcomes in FEP. RESULTS: Drugs and alcohol were associated with lower functioning, but drugs had a greater negative impact on most measures at 2-year follow-up. Half of CUD patients and more than 65% of cocaine or amphetamine abusers presented polysubstance use disorder (poly-SUD). The only group that deteriorated from years 1 to 2 (symptoms and functioning) were patients with persistent CUD alone. Outcome was worse in CUD than in the no-SUD group at 2 years. Cocaine, amphetamines and poly-SUD were associated with worse symptomatic and functional outcomes from the 1st year of treatment, persisting over time with higher service utilization (hospitalization). CONCLUSION: The negative impact attributed to CUD in previous studies could be partly attributed to methodological flaws, like including polysubstance abusers among cannabis misusers. However, our investigation confirmed the negative effect of CUD on outcome. Attention should be paid to persistent cannabis misusers, since their condition seems to worsen over time, and to cocaine and amphetamine misusers, in view of their poorer outcome early during follow-up and high service utilization.

Effects of ß2 agonists on post-thoracotomy pain incidence.

BACKGROUND: Pre-clinical research has shown ß2 -adrenoceptors to be essential for the antiallodynic action of antidepressant drugs in murine models of neuropathic pain and that sustained treatment with ß2 -agonists has an antiallodynic action. Here, we clinically investigated whether chronic ß2 -agonist treatments may influence the incidence of post-thoracotomy chronic pain, defined as pain that recurs or persists along a thoracotomy scar more than 2 months after surgery, either neuropathic or non-neuropathic. METHODS: We conducted an epidemiological study on patients operated by thoracotomy. Demographic data, medical history and treatments concomitant to the surgery were recorded at a follow-up visit. Information on perioperative treatments was collected from the anaesthesia records and confirmed by the patients. In patients with pain at the surgery level, post-thoracotomy chronic pain was assessed by clinical examination and numeric scale. Physical examination and DN4 questionnaire were used to discriminate neuropathic and non-neuropathic chronic pain at scar level. RESULTS: One hundred and eighty-nine patients were included. Eighty-one patients reported persisting thoracic pain, with neuropathic characteristics in 58 of them (30% of the 189 patients). The most common chronic drugs during the perioperative period were inhaled ß2 -agonists (28.6%). The chronic use of ß2 -agonists was an independent predictor of thoracic neuropathic pain (but not of non-neuropathic pain) and was associated with a five-fold decrease in the relative incidence of neuropathic pain [OR = 0.19 (0.06-0.45)]. CONCLUSIONS: These data suggest a possible influence of chronic ß2 -agonist treatments on neuropathic pain secondary to thoracotomy. This apparent preventive effect of ß2 -agonist treatments should warrant controlled clinical trials.