Opioids for the Management of Dyspnea in Cancer Patients: Evidence of the Last 15 Years--A Systematic Review.

The objective of this study was to review the evidence on the use of opioids for treatment of the dyspnea in adult cancer patients. A systematic literature review was conducted in the databases MEDLINE, CINAHL (EBSCO), ScienceDirect, and Cochrane Library of trials testing the effect of opioids in relieving dyspnea in cancer patients. Fourteen trials met the criteria for inclusion in the review. Eight randomized trials and six nonrandomized trials. All randomized clinical trials analyzed present risks of bias. Morphine has been the most studied strong opioid showing efficacy in alleviating dyspnea when administered, either orally or subcutaneously, in cancer patients. The potential benefit of the strong opioids in the alleviation of dyspnea in cancer patients is modest and limited to some opioids. More studies are needed to sufficiently support the role of opioids in dyspnea at rest, at exertion, and for breakthrough dyspnea and to clarify the safety issues.