Alfentanil, but Not Amitriptyline, Reduces Pain, Hyperalgesia, and Allodynia from Intradermal Injection of Capsaicin in Humans

Abstract

These data correspond with previous studies in volunteers demonstrating reduction in hyperalgesia and allodynia after intradermal injection of capsaicin by systemically administered opioids, and they suggest that this reduction may be secondary to reduced nociceptive input by acute analgesia. These data do not support the use of acute systemic administration of amitriptyline for acute pain, hyperalgesia, and allodynia, although the roles of chronic treatment and spinal administration are being investigated.