DOES DETOXIFICATION REVERSE THE ACUTE LUNG INJURY OF CRACK SMOKERS

The effect on chronic crack users of a 3 month detoxification programm e on lung clearance of inhaled Tc-99(m)-diethylenetriamine pentaacetat e (Tc-99(m)-DTPA) aerosol, spirometry and gas exchange was determined in a controlled in-patient clinical treatment setting. Imaging studies were carried out in eight chronic crack users (four crack-only and fo ur crack plus tobacco) before and after the successful completion of t he detoxification programme to measure the clearance of inhaled Tc-99( m)-DTPA from the lungs, an index of lung epithelial permeability. Tc-9 9(m)-DTPA lung clearance, expressed in terms of the biological half-ti me, T-1/2, was determined from the slopes of the least-squares fit reg ression lines of the respective time-activity plots. The mean (+/- S.D .) global T-1/2 values of the crack-only (75+/-39 min) and crack plus tobacco users (22+/-10 min) were significantly shorter (P < 0.02 and P < 0.001, respectively) than from the lungs of the non-smoking control s (124 +/- 29 min). This was consistent with increased lung epithelial permeability secondary to crack-related lung injury. The mean global T-1/2 value of the crack plus tobacco users was significantly shorter (P < 0.05) than that of the crack-only users. After detoxification, th e abnormally rapid lung clearance became normal in two of the four cra ck-only users studied, improved in a third and remained unchanged in t he fourth, a subject whose T-1/2 value was already normal initially. H owever, lung clearance improved in only one of the four crack plus tob acco users studied. Faster Tc-99(m)- DTPA clearance was the only impai rment found in seven of the eight crack users, the eighth having restr ictive lung disease. Crack-related lung injury, reflected by abnormall y rapid Tc-99(m)-DTPA lung clearance, may be at least partially revers ible after a 3 month period of abstinence from crack.