title: Opioids prescription for symptoms relief and the impact on respiratory function: updated evidence.
abstract: OBJECTIVE
  Opioids are used for treating dyspnea and other symptoms in oncological and nononcological patients. The relief of respiratory fatigue and anxiety that these opioids offer is well known. One of the scarcely frequent, but very much feared, side-effects is respiratory depression. The purpose of this review is to determine whether or not the situation of an advanced-stage patient under palliative care and the use of opioids are risk factors for respiratory depression.
  
  
  RESULTS
  Studies conducted on respiratory function and opioids have proliferated in the past 10 years, but there is no recent review that groups the results together and evaluates their safe use in end-stage patients.
  
  
  CONCLUSIONS
  A bibliographic review found three randomized double-blinded placebo-controlled studies and five prospective studies, six of which showed that opioids significantly relieve dyspnea (P<0.001). The use of morphine for symptomatic relief does not significantly change the level of saturation of oxygen in the blood. In addition, the functional studies do not indicate that the use of opioids for dyspnea relief causes high CO2 levels in blood (P=0.05). The opioids used for treating dyspnea do not significantly compromise respiratory function; they are safe and effective.
authors.affiliation: Palliative Care Unit, Clinic University of Navarra, Institute for Culture and Society (ICS), ATLANTES Research Program: Human Dignity, Advance Disease and Palliative Care, University of Navarra, Pamplona, Spain.
authors.forename: José Mario
authors.initials: JM
authors.lastname: López-Saca
authors.forename: Carlos
authors.initials: C
authors.lastname: Centeno
mesh_terms: D000701:Analgesics, Opioid / Q000627:therapeutic use*; D002986:Clinical Trials as Topic; D004417:Dyspnea / Q000188:drug therapy*; D006801:Humans; D009020:Morphine / Q000627:therapeutic use*; D010166:Palliative Care; D012119:Respiration / Q000187:drug effects
chemical_list: D000701:Analgesics, Opioid; D009020:Morphine