US Pharm. 2007;32(10):93-94.

Researchers at the Medical Research Institute of New Zealand found that a single marijuana cigarette smoked by heavy users of marijuana can cause more damage than 2.5 to five "regular" tobacco cigarettes. According to Richard Beasley, MBchB, FRACP, and colleagues, cannabis, the plant source of marijuana and the most widely used illegal drug worldwide, was associated with dose-related impairment of the large airways, causing airflow obstruction and hyperinflation. But interestingly, unlike tobacco smoking, the investigators said that marijuana smoking was rarely associated with macroscopic emphysema.

Some other findings included the fact that cannabis smoking was better associated with decreased lung density on high-resolution CT scans, as was chest tightness, than tobacco. Also, it is more likely that a cannabis smoker will experience chronic bronchitis than a tobacco smoker. However, both chest tightness and coughing were equally associated with cannabis and tobacco smoking.

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