Evaluation of Analgesic Tolerance Induced by Metamizole in the Writhing Test Model

Abstract

Analgesic tolerance is defined as the need for increasing doses to achieve the intended effect. In this paper we present experimental data from the search for analgesic tolerance induced by metamizole in a pain model induced by 0.9% acetic acid known as abdominal constriction test or Writhing test. The aim of this study was to identify the development of analgesic tolerance to metamizole in the Writhing test model. Experimental: groups of Balb/C mice 6±2 were used. They were administered metamizole in different protocols, and subsequently underwent a pain stimulus with 0.9% acetic acid via intraperitoneal, evaluated for 30 minutes and counting time of latency, number of abdominal stretches in order to rate pain response, subsequently naloxone was administered to look for signs of withdrawal. Our results demonstrated that there is a tendency to develop analgesic tolerance to metamizole after its repeated administration.