EXPOSURES OF HEALTH-CARE WORKERS TO RIBAVIRIN AEROSOL - A PHARMACOKINETIC STUDY

We assessed health risks to nurses and therapists exposed occupational ly to ribavirin aerosol, a known rodent teratogen, by measuring uptake as a function of exposure concentration. During a 4-d period, healthy , nonsmoking, young adult volunteers (N = 14) were exposed 4 h/d to re spirable ribavirin aerosol at concentrations that exceeded occupationa l levels. Intermittent exercise occurred during exposure, and all acti vities occurred in a simulated hospital room. Ribavirin was assayed in plasma, red cells, and urine; lung function and symptoms were also me asured. In 7 volunteers who were exposed to 30 mg/m(3) (i.e., received approximate to 10% of therapeutic dose), postexposure ribavirin conce ntrations in plasma and urine were similar on all 4 d, averaging 0.89 mu mol/l and 131 mu mol/l, respectively. These concentrations decrease d after exposure, with half-times of 37-39 h. Red-cell concentrations averaged 31 mu mol/l on d 4, accounting for < 5% of inhaled ribavirin mass, and they remained stable for 4 d afterward. In 7 volunteers expo sed to 3 mg/m(3) (i.e., approximate to 1% of therapeutic dose), plasma averaged 0.075 mu mol/l and red cells averaged 3 mu mol/l on d 4 (i.e ., near detection limits). Small variations occurred in lung function, reported symptoms, and hematologic values for exposures to both 3 and 30 mu g/m(3); therefore, these effects were most likely not caused by ribavirin. Typical occupational exposures to ribavirin, without recom mended protective measures, should result in undetectable or barely de tectable body burdens, i.e., approximately 0.1%-1% of levels reported to be toxic to laboratory animals.