Dose, plasma concentration, and effect of oral terbutaline in long-term treatment of childhood asthma.
Oral terbutaline in gradually increasing doses from 45 to 166 micrograms/kg three times daily was administered to asthmatic school children. There was a linear relationship between dose and steady-state plasma concentration of terbutaline within patients, but the plasma levels varied fourfold between patients taking similar doses. The consumption of beta 2-stimulants in aerosol form decreased, and the symptom score, peak expiratory flow rate, and FEV1 improved during treatment with a roughly linear dose-effect relationship. Significant increases in pulse rate and skeletal muscle tremor were also measurable. There was no clear correlation between plasma levels of terbutaline and reported side effects. Linear regression analysis revealed a statistically significant relationship between bronchodilatation and the same plasma level was considerable. Determination of the plasma terbutaline concentration therefore seems to be of limited value in clinical practice. Instead, the dose should be individualized on the basis of clinical effect and tolerance. Our data indicate that many young asthmatic children will tolerate and sometimes benefit from higher doses than are generally recommended if they are carefully titrated with stepwise increments.
D000284:Administration, Oral; D000293:Adolescent; D001249:Asthma / Q000097:blood / Q000188:drug therapy*; D002648:Child; D004305:Dose-Response Relationship, Drug; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008168:Lung / Q000502:physiology; D008297:Male; D012129:Respiratory Function Tests; D013726:Terbutaline / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D013997:Time Factors; D014202:Tremor / Q000139:chemically induced
D013726:Terbutaline