Saliva composition in asthmatic patients after treatment with two dose levels of a beta 2-adrenoceptor agonist.

Changes are known to occur in the salivary composition of asthmatic patients treated with beta 2-adrenoceptor agonists. To evaluate the precise contribution of the agonist to the impaired saliva secretion, 15 asthmatic patients, 15-23 yr old, were given two dose levels of agonist, either terbutaline or salbutamol. The lower dose, 0.15-3.0 mg/day, represented the therapeutic level used by the patients. During a wash-out period of one month, the asthma was treated with budesonide, a corticosteroid spray. Then a daily dose of 32 mg of terbutaline or salbutamol was given for one month. Samples of whole saliva, stimulated by chewing, and parotid saliva, stimulated by citric acid, were collected on three occasions: (1) at the end of the low-dose agonist treatment; (2) at the end of the wash-out period; and (3) at the end of the high-dose agonist treatment. During the high dosing the secretion rate of parotid saliva decreased and the concentrations of its total protein, amylase, hexosamine and the ratio of hexosamine/total protein were lowered. The output per minute of total protein, amylase, hexosamine, peroxidase, lysozyme, secretory IgA and potassium decreased. There were only small differences in secretion rates or saliva composition between samples collected at the end of the low-dose and at the end of the wash-out period. Thus, treatment with beta 2-adrenoceptor agonists impairs saliva secretion in asthmatics.