Antipyrine Absorption and Disposition in the Elderly

Abstract

Twelve young (24–41 years) and 11 elderly (62–77 years) volunteer subjects received a single 1.0-gram dose of antipyrine on three occasions: intravenously, orally in the fasting state and orally following a standard breakfast. Plasma antipyrine concentrations were determined for 24 h after each dose. Compared to young males, elderly men had significantly prolonged elimination half-life (17 vs. 11 h, p < 0.025) and reduced clearance (32 vs. 54 ml/min, p < 0.06). However, elderly and young women did not differ in half-life (12 vs. 11 h) or clearance (37 vs. 44 ml/min). After oral dosage in the fasting state, young and elderly groups (regardless of gender) did not differ in peak plasma antipyrine concentration (C_max) or time of peak concentration (T_max). Absolute bioavailability was not significantly less than 100 % and was not related to age. Postprandial oral dosage of antipyrine caused reduced C_max and prolonged T_max in all groups, but absolute bioavailability was not significantly less than 100%. Again, there were no age-related differences. Although aging may lead to reduced clearance of antipyrine among men, there is no evidence that old age is associated with impairment of the rate or extent of antipyrine absorption from the gastrointestinal tract.

The Relationship between Phenazone (Antipyrine) Metabolite Formation and Theophylline Metabolism in Healthy and Frail Elderly Women

“…Some investigators have found significantly lower hepatic enzyme activity with age, reflected in a lower CLm,p, whereas others could not detect significant changes in CLm,p (for review see Durnas et al 1990). However, in a recent study it was found that CLm,p decreased in men but not in women (Greenblatt et al 1988). The data presented in that paper show that aging decreases CLm of phenazone, a compound which is more than 95% meClin.…”

Age‐related changes in pharmacokinetics and pharmacodynamics: basic principles and practical applications

“…While some studies have not shown significant age-related differences in absorption rates for different drugs [23,[44][45][46][47][48][49], the absorption of vitamin B 12 , iron and calcium through active transport mechanisms is reduced [22,50] whereas the absorption of levodopa is increased. The latter is probably secondary to a reduced amount of dopadecarboxylase in the gastric mucosa [51].…”

Reproducibility of antipyrine half-lives in elderly subjects

“…One state when they took antipyrine. This introduction of study reported mean antipyrine pharmacokinetics in potentially confounding variables prevented the auelderly men and women measured on three separate thors from drawing any quantitative conclusions on occasion^.^ In each test, however, the subjects had a the extent of intraindividual phannacokinetic variabildifferent route of antipyrine administration; also, some ity in their elderly subject^.^ 8 1 Fig. 2.…”

“…This conclusion was also reached by several other groups who have used antipyrine safely to investigate drug metabolism in the elderly. 8,[11][12][13]15,16 Finally, the clinical significance of high reproducibility of individual pharmacokinetic values in elderly patients merits discussion. If elderly subjects were to demonstrate more intraindividual pharmacokinetic variability than young adults under similar uniform environmental conditions, then pharmacokinetic values obtained only once in an elderly subject would less faithfully reflect over time that subject's drugeliminating capacity.…”