Effect of Ketoconazole on Breathlessness

Beta-endorphins, which are naturally occurring narcotic substances, have been shown to alter the perception of breathlessness. Oral ketoconazole, an antifungal antibiotic, increases blood levels of beta-endorphins. The study hypothesis is that oral ketoconazole will reduce ratings of breathlessness induced by resistive breathing loads.

Beta-endorphins are naturally occurring narcotic substances (like morphine) that are released by the brain under stressful conditions, such as exercise and when breathing through a resistive load (a tube containing fine wire mesh). In one study of 8 patients with coronary artery disease, ketoconazole, an oral medication used to treat fungal infections, was administered (1,200 mg at 12 midnight and 600 mg at 6 am) and increased blood levels of beta-endorphins five fold. In a recent study performed at Dartmouth-Hitchcock Medical Center, we found that ketoconazole increased blood levels of beta-endorphins in all eight patients with chronic obstructive pulmonary disease (COPD). Mean values increased by 2.5 times at four hours compared with baseline values (p = 0.0078). Based on this significant response, we propose to study the effect of ketoconazole on patients' perception of breathlessness induced by resistive breathing loads in a randomized clinical trial. The hypothesis of the study is that ketoconazole will reduce ratings of breathlessness as mediated by the increased levels of beta-endorphins.