Pulmonary function studies in ex-heroin users.

Pulmonary function tests were performed on a group of 22-ex-heroin addicts with no known pulmonary disease or symptoms. Vital capacity and total lung capacity were normal in all but four patients. Only two patients had evidence of moderately severe airway obstruction. However, the single breath diffusing capacity (Dco) was significantly reduced in many of the patients and averaged 81 percent of predicted for the entire group. Patients with most severe reduction of Dco also had reduction of lung volumes. In addition, six patients had increased lung recoil force (Pmax) and decreased lung compliance. There was no correlation between degree of functional impairment and duration or amount of durg use, incidence of overdose or intravenous injection of crushed tablets. Followup studies in four patients after several months on methadone maintenance showed improvement in lung volumes and/or Dco. Possible etiologic considerations to explain these abnormalities were previous subclinical pneumonias, foreign body granulomas, previous pulmonary edema or other direct toxic effect on alveolocapillary membrane as the result of use of drugs.