Nortriptyline and duloxetine are the best, but not great options for managing patients with cryptogenic sensory polyneuropathy (CSPN).
A US study of 402 patients from 40 clinical sites comparing nortriptyline, duloxetine, pregabalin and mexiletine found there was a need for new, more effective drugs for idiopathic neuropathic pain.
The PAIN-CONTRoLS study, published in JAMA Neurology, used a combination of efficacy and drop-out rates at 12 weeks to create a single outcome measure and compare the utility of the four drugs.
It found medication quit rates – for any reason but usually adverse events – were lowest in nortriptyline (38.1%) and duloxetine (37.3%) compared to pregabalin (42,5%) and mexiletine (58.0%).
Efficacy, defined as at least a 50% reduction in pain, was low with all drugs but marginally higher in nortriptyline (25.4%) and duloxetine (23.0%) compared to pregabalin (15.1%) and mexiletine (20.3%).
Combining the outcomes into a utility function score showed nortriptyline (0.81) and duloxetine (0.80) were superior to either pregabalin (0.69) or mexiletine (0.58).
“The probability that the treatment has the best utility was 0.52 for nortriptyline, 0.43 for duloxetine, 0.05 for pregabalin, and 0.00 for mexiletine,” the study said.
It said the findings support duloxetine and nortriptyline as the better-performing drug choices in this patient population with neuropathic pain.
“However, this study also supports a finding that all 4 drugs helped improve pain in at least some patients, so each could be tried if others failed.”
Commenting on the study Dr Neil Simon, from Northern Beaches Neurology and head of neurology at the Northern Beaches Hospital in Sydney, told the limbic the findings were somewhat depressing.