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

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.