Single-blind placebo-controlled response on phenytoin 10% in painful diabetic neuropathy

Abstract

Phenytoin is a broad acting sodium channel blocker, with analgesic properties in animal models and in controlled human clinical trials. The pathogenesis of Painful Diabetic Neuropathy is partly located in the skin, based on the peripheral sensitization of nociceptors and small nerve fibers. We developed a topical formulation of 10% phenytoin cream to treat those patients. Here we describe a classical patient suffering from peripheral symmetrical Painful Diabetic Neuropathy, treated successfully with this cream. We evaluated whether this patient was a responder by applying a placebo-controlled single-blind response test. Pain was reduced from NRS-score 7 to 5 by placebo and from 7 to 0 by phenytoin cream. Based on this positive response test, phenytoin 10% cream was prescribed.

Neuropathic pain due to chronic idiopathic axonal neuropathy: fast pain reduction after topical phenytoin cream application

“…Meanwhile, we use this single-blind response test always before we prescribe phenytoin cream, to rule out placebo-responders already during the fi rst visit. [6,7]…”

Neuropathic pain in chronic idiopathic axonal neuropathy: Fast pain reduction after topical phenytoin cream

“…Here we present a patient suffering from EMG documented CIAP and burning pain, tested for his response to phenytoin 10% cream in a single-blind fashion. Meanwhile, we use this single-blind response test always before we prescribe phenytoin cream, to rule out placebo-responders already during the first visit [6].…”