Eficacia de los opioides tópicos como analgésicos en enfermedades dolorosas cutáneas: revisión de la literatura científica y propuesta metodológica para su evaluación clínica

Abstract

Introduction: Even though it is a common practice in some centers, there is still little evidence that justifies the use of topical opioid-based analgesics in skin and mucosal diseases. Objectives: To review the available scientific literature that justifies the use of topical opioids in the treatment of painful skin and mucosal diseases. Evaluate the analgesic efficacy and adverse effects of topical opioids in the treatment of oral diseases and painful skin diseases. Methods: An electronic search was performed using the following databases and search engines: EMBASE, Medline, SCIELO, LATINDEX, Current Controlled-Trials and academic Google to identify the literature on topical opioids in the treatment of painful skin and oral mucosa diseases. The selection method was based on the combination of different descriptors concerning topical opioids and pain using MeSH vocabulary. The search terms used were "opioid" ''topic'', "analgesic", "ulcer", "mucositis," "peripheral" and combinations of these words. Additional articles were retrieved from the reference lists of papers identified. The final search took place in July 2013. The inclusion criteria for the review were: Human studies, published in Spanish, French, English or German, containing main data on the efficacy of topical opioids as analgesics. We excluded from analysis studies that evaluated the effectiveness of opioids administered by invasive methods (such intrapleural, intravesical, or intraarticular) or ophthalmic administration. Results and conclusions: 28 publications were included from the search, 11 corresponded to prospective, randomized, controlled trials. The duration of randomized studies was short, with a following period of one week or less. There isn't however enough information to compare studies because of the heterogeneity of populations and treatments. The studies that controlled systemic levels of opioids comment conflicting results regarding the absorption of topical opioids through ulcerated skin, possibly associated with variables such as drug preparation, dosage, application extension and duration of treatment. Regarding adverse effects, these are minimal in appearance and limited to local reactions, and those studies that report these do not determine a definitive causal relationship.