Decreased single breath carbon monoxide diffusing capacity in cocaine freebase smokers.

The authors performed pulmonary function tests on 10 chronic cocaine freebase smokers. Testing occurred at least 2 weeks after stopping cocaine use. Mean single breath carbon monoxide diffusing capacity (DLCOSB) was significantly reduced (P less than 0.05) in the cocaine smokers when compared with a control group of non-smokers and non-drug users. All other parameters of lung function were normal. Since most of the cocaine smokers also smoked tobacco, the observed abnormality may have been due to an additive effect of the 2 substances. The authors conclude that smoking cocaine may damage the gas exchange surface of the lung.