Tremor measurement in asthma. II. Changes after terbutaline administration suggesting beta-adrenergic blockade

Repeated finger tremor measurements have been performed in six normal and eight asthmatic subjects after subcutaneous and oral administration of terbutaline. Prior to the investigations the patients had not used bronchodilators for 10-14 days. The finger tremor pattern showed a striking parallelism with the terbutaline serum concentrations and with the cAMP plasma levels. After subcutaneous administration the increase in tremor values in asthmatic subjects was significantly less than in normals. This suggests a beta-blockade in skeletal muscle of asthmatics. The difference after oral administration was not statistically significant.