Metronidazole clearance: A one‐sample method and influencing factors

After 96 administrations of metronidazole to 36 subjects, it was found that the clearance could be determined from one plasma sample, the dose, and a volume of distribution estimated from sex, age, body weight, and height, without loss of precision and accuracy compared with conventional clearance determinations (r > 0.97). In 230 sample pairs the plasma and saliva concentrations of metronidazole were identical (r = 0.99). In 119 subjects the one‐sample clearance of metronidazole was unimodally distributed. Body weight (r = 0.28) and the alcohol consumption (r = 0.23) correlated with the metronidazole clearance. In the same subjects the consumption of tobacco (r = 0.28), alcohol (r = −0.19), coffee/tea (r = 0.27), age (r = −0.24), and sex (r = 0.28) correlated with the antipyrine clearance. The clearances of metronidazole and antipyrine were correlated (r = 0.34). The differential influence of the environmental factors on the elimination rates supports differential metabolism of metronidazole and antipyrine. Clinical Pharmacology and Therapeutics (1988) 43, 420–428; doi: 10.1038/clpt.1988.53