Treating Pain in Diabetic Neuropathy: Current and Developmental Drugs.

There is a high prevalence of painful diabetic polyneuropathy (pDPN) with around one-third of all patients with diabetes suffering from pDPN. pDPN has debilitating consequences, with a major impact on morbidity and quality of life. Unfortunately, there is no globally licenced pharmacotherapy that modulates the underlying disease mechanisms to prevent or halt the progression of diabetic neuropathy. The cornerstone of treatment therefore remains optimising glycaemic control and cardiovascular risk factors, and symptom control. Evidence from placebo-controlled studies has shown that antidepressants and anticonvulsants are effective for alleviating pDPN. Current clinical guidelines recommend the treatment of pDPN through the use of amitriptyline (tricyclic antidepressant), duloxetine (serotonin norepinephrine reuptake inhibitor), gabapentin and pregabalin (α2-δ ligands), tramadol and tapentadol (μ receptor agonists and norepinephrine reuptake inhibitors) and topical agents such as capsaicin (transient receptor potential V1 receptor desensitizer), although the latter is known to cause degeneration of small nerve fibers. pDPN can be difficult to treat, which frustrates healthcare providers, patients and caregivers. There is an additional need for clinical trials of novel therapeutic agents and optimal combinations for the management of pDPN. This article reviews the pharmacological management of pDPN, emerging therapies, the difficulties of placebo response in clinical trials and novel proposed biomarkers of treatment response.