The effects of morphine on dyspnea and ventilatory function in elderly patients with advanced cancer: A randomized double-blind controlled trial

Background: Dyspnea represents a very frequent and distressing symptom in patients with advanced cancer. This study was undertaken to assess the efficacy of morphine on dyspnea and its safety for ventilatory function in elderly advanced cancer patients. Patients and methods: Nine elderly patients with dyspnea due to lung involvement were randomized to receive either morphine subcutaneously (5 mg in seven opioid-naive patients and 3.75 mg in two patients on top of their regular oral dose of 7.5 mg q4h) or placebo on day 1. On day 2, they were crossed over to receive the alternate treatment. Dyspnea was assessed every fifteen minutes using a visual analogue scale (VAS: 0-100 mm) and the ordinal scale developed by Borg (0-10 points). Pain, somnolence and anxiety were assessed using VAS. Respiratory effort, respiratory rate and oxygen saturation were also measured repeatly. Results: Mean changes in dyspnea 45 minutes after injection were -25 +/- 10 mm and -1.2 +/- 1.2 points for morphine, versus 0.6 +/- 7.7 mm (P < 0.01) and -0.1 +/- 0.3 points (P = 0.03) for placebo on VAS and Borg scale, respectively. No relevant changes were observed in somnolence, pain, anxiety, respiratory effort and rate, and oxygen saturation. Conclusions: Morphine appears effective for cancer dyspnea, and it does not compromise respiratory function at the dose level used.