Assessment of exposure to chloramphenicol and azathioprine among workers in a South African pharmaceutical plant.

There have been very few published studies that have evaluated exposure to myelotoxic drugs among production workers in pharmaceutical plants. Previous studies have focussed mainly on nurses and evaluated exposure to cytotoxic drugs using urine mutagenicity as a marker of exposure. The aim of this study was to evaluate the exposure of workers involved in the production of chloramphenicol and azathioprine. Exposure was evaluated utilising biological monitoring, biological effect monitoring and environmental monitoring. Biological monitoring included plasma chloramphenicol levels, plasma 6-mercaptopurine and urine 6-thiouric acid levels. These were analysed using high performance liquid chromatography. Myelotoxic effect was assessed by measuring the haematological indices of bone marrow function. The exposed 17 workers were compared to matched controls of equal numbers. Neither substance could be detected in serum nor urine by the analytical methods employed. However, haematological indices demonstrated a significantly decreased mean reticulocyte and neutrophil count in the azathioprine exposed group. Industrial hygiene measurements demonstrated contamination of the air inside the airhood of exposed workers. In conclusion, it is evident that workers involved in the production of both these drugs are at risk of developing adverse health effects. Furthermore, more sensitive analytical methods need to be developed to evaluate absorption of myelotoxic chemicals among occupationally exposed workers.