Dose dependence of the14C-aminopyrine breath test

Abstract

Although the aminopyrine breath test has received much attention, the question has not yet been settled whether pharmacological or tracer doses of the drug should be used. Nine volunteers were given¹⁴C-aminopyrine 9 mg/kg or a tracer amount, in a randomized sequence and according to a crossover design. The specific activity of¹⁴CO₂ in breath was significantly different only during the first hour. Up to the 8th hour the disappearance of¹⁴CO₂ from breath was smaller after the pharmacological (28.5±SD 5.4%/h) than after the tracer dose (36.2±10.6%/h; p14C-atoms from the subjects was significantly slower after the higher dose. In view of the smaller radiation exposure and the decreased risk of agranulocytosis, the use of a tracer dose appears preferable.