Variation in theophylline clearance rate with time in chronic childhood asthma

The Effect of Age, Gender, and Sexual Maturation on the Caffeine Breath Test

“…Gender-related differences in theophylline clearance similar to the gender-related differences in the CBT have been reported in some theoph ylline studies in children and adolescents [3,5,6]. However, other studies did not support these findings [2,7], The discrepancy between the theoph ylline studies may be explained by subject selection as demonstrated by the CBT.…”

“…However, other studies did not support these findings [2,7], The discrepancy between the theoph ylline studies may be explained by subject selection as demonstrated by the CBT. The studies which showed a gender-related difference in theophyl line clearance [3,5,6] primarily used subjects in midpuberty, the stage of sexual maturation with the most significant gender-related difference in the CBT. The theophylline studies [2,7] which did not demonstrated a gender-related difference in clearance, used subjects primarily of an age when the subjects would be either pre-or postpubescent; i.e., pubertal stages where the CBT did not show a gender-related difference.…”

Prepeak of trolox caused by theophylline and its application to the determination of theophylline in rat plasma

“…However, the use of theophylline is often restricted by its narrow therapeutic range (adults, 56-111 lmol L À1 (i.e., 10-20 lg mL À1 ); infants, 28-72 lmol L À1 (i.e., 5-13 lg mL À1 )) [2,3] and various side effects occur when plasma levels exceed 111 lmol L À1 [3][4][5]. The rate of metabolism of theophylline varies considerably from one individual to another [6,7]. Therefore, effective and safe theophylline therapy requires dose optimization by measuring theophylline concentration in plasma.…”

The effect of assay methods on plasma levels and pharmacokinetics of theophylline: HPLC and EIA.

“…For bronchodilation, a narrow therapeutic range of about 10-20 gg/ml (Hendeles et al, 1977;Jenne et al, 1972;Koup et al, 1976;Weinberger & Riegelman, 1974) is generally required. In addition to such a low therapeutic index of the drug, inter- (Ellis, Koysooko & Levy, 1976;Hendeles et al, 1977;Jenne et al, 1972;Kordash, Van Dellen & McCall, 1977;Koup et al, 1976;Mitenko & Ogilvie, 1973a & b;Powell, Vozeh, Hopewell, Costello, Sheiner & Riegelman, 1978;Weinberger et al, 1976) and even intra-subject (Leung, Kalisker & Bell, 1977;Walson, Strunk & Taussig, 1977) variabilities in rate of theophylline 0306-525 1/79/040333-09$01.00 metabolism or total clearance give marked influence on the plasma or serum level of the drug. Thus, the optimization by monitoring plasma or serum level of theophylline therapy is essential, which will inevitably require the pharmacokinetic principles (Ellis, Koysooko & Levy, 1976;Hendeles et al, 1977;Koup et al, 1976, Leung, Kalisker & Bell, 1977Mitenko & Ogilvie, 1973b;Walson, Strunk & Taussig, 1977).…”