Revista Brasileira de Anestesiologia
Print version ISSN 0034-7094
LEAL, Plínio da Cunha; CLIVATTI, Jefferson; GARCIA, João Batista Santos and SAKATA, Rioko Kimiko. Opioid-induced hyperalgesia (OIH). Rev. Bras. Anestesiol. [online]. 2010, vol.60, n.6, pp. 643-647. ISSN 0034-7094. http://dx.doi.org/10.1590/S0034-70942010000600011.
BACKGROUND AND OBJECTIVES: Opioids are commonly used for pain control; however, they can cause hyperalgesia. The reason why this can happen is not known. The objective of this review was to describe the mechanisms, factors implicated, and drug modulation. CONTENTS: The factors implicated in the development of opioid-induced hyperalgesia (OIH), such as duration of use, dose, and type of opioids are described. Mechanisms involved include the glutamatergic system and N-methyl-D-aspartate receptors (NMDA), spinal cyclooxygenase (COX) activation, excitatory amino acids, dynorphin, cytokines and chemokines; prostaglandins, and descending facilitation. Modulation of hyperalgesia could be done through: NMDA receptor antagonists, alpha2-adrenergic agonists, and COX inhibitors. CONCLUSIONS: This is a very complex subject, which involves a series of pathophysiological mechanisms that could contribute for OIH and patient discomfort, bringing disastrous consequences.
Keywords : ANALGESICS [Opioids]; COMPLICATIONS [hyperalgesia].