Plasma β-Endorphin Is Not Affected by Treatment with Imipramine or Paroxetine in Patients with Diabetic Neuropathy Symptoms

Abstract

To determine the possible role of endogenous opioid peptides in the action of imipramine and paroxetine in painful diabetic neuropathy, β-endorphin concentrations in plasma were measured in 20 patients during a doubleblind, placebo-controlled randomized three-way crossover trial. Despite a significant reduction in neuropathy symptoms during both imipramine and paroxetine treatment, the p-endorphin level was unaltered throughout the study. The plasma concentration of p-endorphin was not related to plasma drug concentrations. Thus, this study does not provide evidence of a role of endogenous opioid peptides in the mechanism of action of imipramine and paroxetine in painful diabetic neuropathy.