title: Topical amitriptyline and ketamine for post-herpetic neuralgia and other forms of neuropathic pain.
abstract: BACKGROUND
  Neuropathic pain (NP) has several therapeutic options but efficacy is limited and adverse effects occur, such that additional treatment options are needed. A topical formulation containing amitriptyline 4% and ketamine 2% (AmiKet) may provide such an option.
  
  
  METHODS
  This report summarizes both published and unpublished results of clinical trials with AmiKet. In post-herpetic neuralgia (PHN), AmiKet produces a significant analgesia which is comparable to that produced by oral gabapentin. In diabetic painful neuropathy, AmiKet showed a strong trend towards pain reduction. In mixed neuropathic pain, case series reports suggest a favourable response rate, but are limited by trial characteristics. AmiKet is absorbed minimally following topical administration. Over 700 patients have now received topical AmiKet in clinical regimens, and it is well-tolerated with the adverse effects mainly being application site reactions. Both agents are polymodal, and several mechanisms may contribute to the peripheral efficacy of AmiKet.
  
  
  CONCLUSIONS
  Topical AmiKet has the potential to be a first-line treatment option for PHN, and to be useful in other NP conditions. Furthermore, AmiKet has the potential to be an adjunct to systemic therapies, with the targeting of a peripheral compartment in addition to central sites of action representing a rational drug combination.
authors.affiliation: a Department of Pharmacology , Dalhousie University , Halifax , Canada.
authors.forename: Jana
authors.initials: J
authors.lastname: Sawynok
authors.affiliation: b VeraMed Consulting, Ltd , Mahe , Seychelles.
authors.forename: Celia
authors.initials: C
authors.lastname: Zinger
mesh_terms: D000287:Administration, Topical; D000639:Amitriptyline / Q000494:pharmacology / Q000627:therapeutic use*; D000700:Analgesics / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D003929:Diabetic Neuropathies / Q000188:drug therapy; D004338:Drug Combinations; D006801:Humans; D007649:Ketamine / Q000494:pharmacology / Q000627:therapeutic use*; D009437:Neuralgia / Q000188:drug therapy*; D051474:Neuralgia, Postherpetic / Q000188:drug therapy; D059408:Pain Management
chemical_list: D000700:Analgesics; D004338:Drug Combinations; D000639:Amitriptyline; D007649:Ketamine
keywords: amitriptyline; ketamine; neuropathic pain; topical analgesics