title: Topical analgesics.
abstract: OBJECTIVE
  Pain treatment involves the usage of common and opioid analgesics, nonsteroidal anti-inflammatory drugs (NSAIDs) and adjuvant analgesics. Traditionally, these drugs are administered systemically or into the neuraxis. However, when analgesics are applied through these pathways, they are associated with significant side effects, which can hinder its use. Topical administration of analgesics is an alternative. The objective of this paper is to discuss topical analgesics, the mechanisms of action and clinical efficacy.
  
  
  BACKGROUND
  This is a review paper addressing the usage of the topical local anesthetics: capsaicin, clonidine, tricyclic antidepressants, ketamine, opioids and cannabinoids, discussing mechanism of action and effectiveness.
  
  
  CONCLUSIONS
  Topical analgesics are promising as a strategy for pain treatment, as they are associated with lower incidence of side effects. The benefit of local anesthetics, NSAID's and capsaicin is well established. However, the efficacy of clonidine, tricyclic antidepressants, ketamine, opioids and cannabinoids is still questionable. Studies have shown that the multimodal approach is an alternative, but studies are needed to confirm this hypothesis.
authors.affiliation: Anesthesiology Program, Santa Casa de Misericórdia da Bahia, Rua Marechal Floriano 420, Canela, Salvador, BA, Brazil. murilo_flores@yahoo.com.br
authors.forename: Murilo Pereira
authors.initials: MP
authors.lastname: Flores
authors.forename: Anita Perpetua Carvalho Rocha de
authors.initials: AP
authors.lastname: Castro
authors.forename: Jedson dos Santos
authors.initials: Jdos S
authors.lastname: Nascimento
mesh_terms: D000287:Administration, Topical; D000700:Analgesics / Q000008:administration & dosage*; D006801:Humans; D010146:Pain / Q000188:drug therapy*
chemical_list: D000700:Analgesics