Effects of 'crack' cocaine on pulmonary alveolar permeability.
BACKGROUND
Lung clearance of 99mTc-labeled diethylenetriamine pentaacetate (DTPA) is a sensitive test of altered alveolar epithelial permeability that has been found to be increased in smokers of tobacco, as well as a small number of healthy smokers of crack cocaine, suggesting the possibility of subclinical crack-related lung injury.


OBJECTIVE
To evaluate further whether habitual smoking of cocaine alone alters alveolar permeability, whether crack smoking adds to or potentiates the effects of tobacco and/or marijuana, and whether experimental cocaine smoking acutely alters DTPA lung clearance.


METHODS
Observational cohort study (habitual cocaine smoking) and single-blind crossover study (experimental cocaine administration).


METHODS
Fourteen habitual smokers of cocaine alone (CS), 19 smokers of cocaine and tobacco (CTS), 3 smokers of cocaine and marijuana, 12 smokers of cocaine, tobacco, and marijuana (CMTS), and 5 smokers of marijuana plus tobacco (MTS). Results obtained in the crack-smoking subjects were compared with data previously obtained in 10 nonsmokers (NS), 9 smokers of tobacco alone (TS), 10 smokers of marijuana alone (MS), and 4 additional MTS.


METHODS
Subjects underwent measurements of DTPA radioaerosol lung clearance after refraining from marijuana and/or cocaine for > 12 h and from tobacco for >2 h. Ten of the 48 crack users were tested on two days 1 to 2 weeks apart within 2 h of experimental smoking of three physiologically active or inactive doses (total 98.8+/-15.5 or 8.5+/-2.5 mg, respectively) of cocaine base. Lung clearance half-times (T1/2) were computed from time-activity curves for each lung.


RESULTS
T1/2 values for each lung in CS and MS were comparable to those of NS, while TS, MTS, CTS, and CMTS had significantly shorter clearance rates than NS (p<0.01; three-way analysis of variance). No additive or interactive effects on T1/2 were noted among tobacco, cocaine, and/or marijuana. No acute effect of experimental cocaine smoking on T1/2 was noted.


CONCLUSIONS
Whereas regular smoking of tobacco alone or with other substances increases alveolar epithelial permeability, habitual smoking of cocaine and/or marijuana has no measurable effect on alveolar permeability in the absence of tobacco nor any additive effect to that of tobacco alone.
Tashkin
D P
DP
Department of Medicine, UCLA School of Medicine, Los Angeles, CA 90095-1690, USA.
Kleerup
E C
EC
Hoh
C K
CK
Kim
K J
KJ
Webber
M M
MM
Gil
E
E
D000328:Adult; D015824:Blood-Air Barrier / Q000187:drug effects*; D016022:Case-Control Studies; D016578:Crack Cocaine / Q000494:pharmacology*; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008385:Marijuana Smoking / Q000503:physiopathology; D011650:Pulmonary Alveoli / Q000187:drug effects* / Q000503:physiopathology; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D016037:Single-Blind Method; D012907:Smoking / Q000503:physiopathology; D019966:Substance-Related Disorders / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016284:Technetium Tc 99m Pentetate
D016578:Crack Cocaine; D019275:Radiopharmaceuticals; D016284:Technetium Tc 99m Pentetate