Environmental factors affecting paracetamol metabolism in London factory and office workers

Paracetamol elimination was measured, using serial saliva samples, in 114 London factory and office workers, 76 whites and 38 Asian immigrants. Use of social drugs such as alcohol, tobacco and the oral contraceptive varied considerably within the sample, being appreciably greater in white subjects. Paracetamol clearance was 21 percent slower in Asians than in whites and half-life 18 percent longer. The total range of clearance was 1.86-6.78 ml/min/kg. Clearance was slower in women than in men, increased with increasing alcohol intake and cigarette consumption, and was more rapid in those women using the oral contraceptive. The effects of alcohol and the oral contraceptive were also found in white subjects alone. The variable found to correlate independently with paracetamol clearance accounted for only 27 percent of the total sample variance, however, and are unlikely to be the major determinants of paracetamol elimination in man (AU)

Assessment of antipyrine kinetics by measurement in saliva

The half-life of antipyrine has been estimated from saliva samples in ten subjects by a gas chromatographic method. Half-life, apparent volume of distribution and total body clearance estimated from saliva and plasma concentrations of antipyrine are not significantly different. The concentration of antipyrine in saliva is independent of the flow rate within the range expected in healthy subjects in response to mechanical and sapid stimuli. Antipyrine estimation in saliva could facilitate many areas of pharmacokinetic research limited by the difficulty of obtaining serial plasma samples. (AU)