Nebulized Morphine for the Treatment of Dyspnea in Cancer Patients

Abstract

Objective:

To review the literature concerning the use of nebulized opioids to treat dyspnea in terminally ill cancer patients.

Data Sources:

English-language journal articles were obtained by a MEDLINE search (1966-August 1997).

Study Selection:

All clinical trials and case reports involving nebulized opioids. Representative studies discussing neurogenic inflammation and pulmonary opioid receptors were also reviewed.

Data Extraction:

Studies were selected for review on the basis of study design and use of nebulized opioids. Case reports were selected from the palliative care literature.

Data Synthesis:

High-density, low-affinity opioid receptors have been identified in lung tissue and may play a role in the alleviation of dyspnea in some patients. The activation of these receptors in the lung may attenuate the release of inflammatory mediators and neuropeptides such as substance P. However, because nebulized opioids are absorbed buccally or through the airway mucosa, the relief observed may be due to a central rather than peripheral effect.

Conclusions:

Several case reports in the palliative care literature have described favorable results when nebulized opioids are used to treat dyspnea. However, data from controlled trials in populations other than patients with cancer do not substantiate the use of nebulized opioids. Unfortunately, controlled clinical trials have not been conducted in cancer patients; thus, extrapolation is difficult. Well-designed clinical trials in patients with cancer are necessary to determine the efficacy of nebulized morphine in treating dyspnea.