Relationship of Serum Theophylline Concentrations to Histamine-Induced Bronchospasm

Abstract

This study was performed in a randomized double-blind manner on 6 separate days in 10 asthmatic patients to investigate the effect of a sustained theophylline on baseline bronchial hyperreactivity to histamine in relation to the theophylline serum levels and the degree of bronchodilatation produced. No significant bronchodilatation was seen after theophylline administration at every time of evaluation. An improvement of PD₂₀ values of histamine was observed after 4 h (p < 0.05), 8 h (p < 0.01) and 12 h (p < 0.05) from theophylline administration versus respective PD₂₀ values obtained with placebo at the same times. No significant correlation was found between serum theophylline levels and percentage change of PD₂₀ values after drug administration (r = 0.250). We observed an improvement of PD₂₀ mean values in relation to the maximal serum theophylline concentration but our study failed to correlate the degree of protection with serum concentration

Effect of Three Different Doses of a Slow-Release Theophylline Formulation on Bronchial Response to Inhaled Methacholine in Asthmatic Patients

“…In other studies [5,8], no correlation was detected between the protective effect of theophylline on histamine or methacholine challenge and theophylline plasma con centration, possibly because the comparison was between and not within subjects.…”

Annual Review of Chronopharmacology. Volume 7. Biological Rhythms and Medications. Proceedings of the Conference of Chronopharmacology Held in Nice, France on 12-15 March 1990

“…Several studies have documented the ability of theophylline to reduce the bronchoconstrictive effects of histamine (Cartier eta. 1986) (Crimi et al 1987), histamine and methacholine . These studies, however, are contradicted by other work (Dutoit et al 1987) (Cockcroft et al 1989).…”

Attenuation of propranolol-induced bronchoconstriction by frusemide.

“…This study did not nerves. 6 Finally, the cromones sodium cromoglycate and nedocromil sodium have been address the repeatability of the bronchoconstrictor effect of propranolol, which is shown to attenuate propranolol-induced bronchoconstriction. It is likely that they are acting known to be moderate or good.…”