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SNRIs first-line therapy for diabetic peripheral neuropathy pain

By Nicole MacKee
The serotonin and noradrenaline reuptake inhibitors (SNRIs) duloxetine and venlafaxine should be first-line therapy in managing diabetic peripheral neuropathy pain, says an Australian expert. 

Commenting on a systematic review in Neurology, Professor Stephan Schug, Director of Pain Medicine at the Royal Perth Hospital, said there was universal agreement that SNRIs should be the first choice for clinicians treating patients with diabetic polyneuropathy and this was reinforced by the review’s findings. 

The systematic review of 106 studies found moderate strength evidence to support the use of duloxetine and venlafaxine for reducing neuropathy-related pain, and low strength evidence for using the anticonvulsants pregabalin and oxcarbazepine, tricyclic antidepressants, atypical opioids and botulinum toxin. 

‘These are mainly elderly patients, so tricyclic antidepressants are possibly a high risk, and pregabalin increases sedation, which is another problem,’ Professor Schug told Pain Management Today. Professor Schug, who is also Professor and Chair of Anaesthesiology at the University of Western Australia, said pregabalin would be second choice in these patients, followed by tricyclic antidepressants, if there are no contraindications to these, and then tapentadol and tramadol. 

Professor Schug said it was not surprising to find evidence to support the two atypical opioids because tramadol and the newer tapentadol both have a significant noradrenaline reuptake inhibition component that is beneficial in neuropathic pain. 
‘[Researchers] have now identified three randomised controlled trials [that have shown tapentadol to be effective], on which basis they have also registered tapentadol for diabetic neuropathy in the USA,’ he said. ‘Clearly, tapentadol is the better [atypical opioid] because it is free of the serotonin effects that often cause problems in the elderly using tramadol,’ he said. 

He said it was important to note that conventional opioids were not recommended for diabetic polyneuropathy. ‘[Opioids] have only poor pain-relieving effects as shown in the review and [result in] deteriorating quality of life, so conventional opioids should not be used in neuropathic pain,’ he said. 

Professor Schug said the researchers had employed an ‘aggressive methodology’ in assessing the data, which may downplay the effectiveness of these therapies. But, he said, the findings were in line with a 2015 systematic review and meta-analysis (Lancet Neurol 2015; 162-173).

Effects on quality of life were also explored in the systematic review but the researchers found insufficient evidence to draw any conclusions.
Neurology 2017; 88: 1-10.

Photo credit © Carol & Mike Werner/SPL/