Clinical science
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Randomized Controlled Trial Comparative Study Clinical Trial
Effects of inhaled nebulized morphine on ventilation and breathlessness during exercise in healthy man.
1. Nebulized inhaled morphine has been reported to increase exercise endurance in patients with chronic lung disease and to relieve dyspnoea in patients with malignant disease. Potential mechanisms include a central effect occurring after systemic drug absorption or a local action mediated by receptors in the lung. 2. ⋯ Intravenous morphine 2.5 mg reduced breathlessness slightly at the highest equivalent workload [mean (least significant range) 33 mm (26-40 mm)] compared with placebo [41 mm (34-48 mm), P < 0.05] but had no other significant effects. 5. These results do not support the hypothesis that intrapulmonary opiate receptors modulate the sensation of breathlessness in healthy man. The possibility that inhaled morphine may affect breathlessness caused by other factors, such as disease, has not been excluded.