Effects of time of dosing and age on intravenous aminophylline pharmacokinetics.

Abstract

The elimination kinetics of theophylline were investigated following intravenous administration of aminophylline in 12 subjects (six fit young, and six healthy hospitalised elderly volunteers) at 09.00 h and 21.00 h on separate occasions at least 5 days apart to determine whether time of administration had significant effects on clearance in young and elderly subjects. We were unable to demonstrate a significant change in kinetic parameters between morning and evening administration in either young or elderly subjects. Our results also demonstrated no difference in kinetics between young and elderly subjects. We conclude that neither time of dosing nor age are important determinants of theophylline elimination kinetics in healthy subjects.

Diurnal variation in CYP1A2 enzyme activity in South Asians and Europeans

“…Diurnal variation in the pharmacokinetics of intravenously administered theophylline, which is a drug predominantly metabolised by CYP1A2, has been reported, with higher concentrations observed in the morning . Similarly, the theophylline prodrug aminophylline (also a CYP1A2 substrate) was found to have significant pharmacokinetic changes related to time of administration . Some proteins, such as the endogenous CYP1A2 substrate melatonin, have demonstrated time‐variable pharmacokinetics in mice when exposed to various periods of light…”

Efficacy and safety of intravenous theophylline administration for treatment of mild acute exacerbation of bronchial asthma

“…In order to avoid theophylline overdose, 22 of 24 patients with <13 µg/mL of theophylline in their blood were selected for the study. According to pharmacokinetic data, 13,14 it was assumed that if the initial theophylline serum concentration was <13 µg/mL, it would not exceed 20 µg/mL after a 2 h intravenous infusion of 200 mg of theophylline in a patient with a bodyweight of 50 kg. Recruitment of patients occurred randomly without any prior information or awareness.…”

Lack of effect of flosequinan on the pharmacokinetics of theophylline.

“…Following centrifugation of blood samples, plasma was separated and stored at -20°C until analysis for theophylline by high performance liquid chromatography (h.p.l.c.) (Rodgers et al, 1987). Pre-dose samples were analysed for caffeine (Rodgers et al, 1987) as a measure of dietary compliance.…”

“…(Rodgers et al, 1987). Pre-dose samples were analysed for caffeine (Rodgers et al, 1987) as a measure of dietary compliance.…”

“…(Rodgers et al, 1987). Pre-dose samples were analysed for caffeine (Rodgers et al, 1987) as a measure of dietary compliance. An aliquot of urine was stored at -20°C until analysis for theophylline and its metabolites 3-methylxanthine (3MX), 1-methyluric acid (1-MU), 1,3-dimethyluric acid (1,3-DMU) and 1-methylxanthine (1-MX), as well as caffeine and one of its major metabolites, paraxanthine (1,7-dimethylxanthine) (Muir et al, 1980).…”