On the specificity of the aminophenazone breath test

In 15 patients suffering from ulcer of the stomach or the duodenum, but without liver disease, the demethylation capacity was studied by the use of 14C-aminophenazone before and under the treatment with the H2-blocker cimetidine in daily doses of 1.0 g. As a measure of demethylation the expired 14CO2 (DPM/mmol CO2/70 kg body weight) was used before and 1 h after intake. Under cimetidine the mean 14CO2-value decreased from 724.7 DPM (SD 127.7 DPM) to 404.1 DPM (SD 153.1 DPM). In 3 patients the cimetidine medication was continued for additional 6 to 8 weeks with a dosage of 0.4 per day. In these subjects a mean of 533.2 DPM was measured. The enzyme activities (ALAT, ASAT, AP, AAP, gamma-GT, ChE) and the albumin and bilirubin concentration in serum measured concomitantly to the ABT did not differ from control values. Thus, the ABT is a useful test to assess changes of the demethylation capacity that can be caused by drugs or xenobiotics without affecting biochemical parameters used for diagnosis of liver diseases. The ABT might be a useful and simple technique to discover environmental disorders due to occupational conditions.