Theophylline therapy in asthmatic children: single-dose studies

Summary

Theophylline is still the corner-stone of long-term bronchodilator therapy in children with chronic bronchial asthma in the U.S.A., hence the importance of selecting aprepar-ation which will achieve therapeutic plasma levels with a minimum of side-effects when a convenient form is complied with in a practical regimen.

A theophylline solution (‘Theolair”) was evaluated in single-dose clinical studies in 16 children with reversible chronic obstructive airway disease {asthma). Theophylline blood levels, pulmonary function clinical parameters and side-effects were monitored serially over a 6-hour period following a single dose (5 mg/kg) of the preparation. Fifteen minutes after the dose the mean plasma theophylline concentration was 8.5 μg/ml which was double the initial baseline level. Mean levels of 10 μgjml were reached at ± hour and maintained for about 2 hours. Meanpeak concentrations of 11.28 μg/ml were achieved at 1 hour. Levels at 6 hours were significantly higher than baseline and very close to levels considered therapeutic. A 20% improvement in FEV₁ was reached within ½ hour with maximal improvement of 25% at 2 hours. FEV₁, measurements were statistically greater (p < 0.001) than baseline values throughout the 6-hour study period. Pulmonary function parameters correlated well with the theophylline level at all times during the 6-hour period. No side-effects were documented clinically throughout the study. These findings suggest that the preparation studied can be used with an appreciable degree of clinical efficacy and safety in the paediatric age group.

Key Words::

• Theophylline
• biological availability
• dosage forms
• child
• asthma