Effect of oral prophylactic broad spectrum nonabsorbable antibiotics on the gastrointestinal absorption of nutrients and methotrexate in small cell bronchogenic carcinoma patients

Abstract

Patients with small cell bronchogenic carcinoma, in a study utilizing laminar-air-flow-protected environments, oral prophylactic broad spectrum non-absorbable antibiotics (PNAA), and intensive combination chemotherapy, were examined to determine the effects of PNAA on serum biochemical values and on gastrointestinal absorption of both nutrients and methotrexate. With use of PNAA the following abnormalities were observed; serum carotene and folate decreased, D-xylose absorption was impaired, fat globules and muscle fibers were demonstrable in the stool, and the mean weight loss in 6 weeks was 10.2% as compared with 4.3% in patients not treated with antibiotics. Methotrexate absorption decreased from a mean of 69% prior to antibiotic use to 44% on PNAA. Thus, PNAA causes malabsorption of both nutrients and drugs. It appears unwise to treat patients on PNAA with oral antineoplastic drugs. Nutritional status must also be closely monitored and supplemental nutrition, either intravenously or with elemental diets, must be considered.