Objective: A review of the evidence was conducted regarding asthma associated with the use of cocaineheroinand marijuana.

Data sources: A search of the English literature was performed via PubMed/Medline and EMBASE using the search terms asthma AND cocaineheroinand marijuana. When pertinent articles were foundsalient references in those articles were assessed.

Study selection: Due to the relatively small number of studieswe included all studies and cases.

Results: For several decadescase reportsretrospective studiesand laboratory investigations have demonstrated that inhalation of cocaine or heroin is associated with increased asthma symptoms and reduced pulmonary function. Smoking crack cocainenasal insufflation of cocaine or heroinand smoking heroin increases the risk of emergency department visits and hospitalizations for asthma. Although frequent smoking of marijuana may cause symptoms of coughsputum productionand wheezing in the general populationmore studies are needed specifically in patients with asthma. Smoking marijuana with concomitant tobacco use is common and further worsens the respiratory symptoms.

Conclusions: Use of cocaine and heroin in patients with asthma should be avoided. Pending further studiesit would be prudent for patients with asthma to avoid smoking marijuana. Clinicians need to be vigilant regarding use of these drugs in their patients with hyperreactive airway disease.