Risk/benefit ratio of long-term treatment with beta 2-adrenoceptor agonists.

Optimal control of chronic obstructive airway disorders is usually achieved with therapy based on beta 2-adrenoceptor agonist administration. Aerosols are highly effective, have few side effects, allow for fine adjustment of dosage to titrate symptoms, and result in reduction in hyperreactivity. Equivalent bronchodilating doses of oral agents cause side effects that limit acceptability. With oral agents, cardiohemodynamic disturbances are usually minor, while tremor and restlessness diminish with continued drug use. In chronic regimens, an aerosol beta 2-adrenergic agent should be chosen whose overall incidence of side effects is less than 5%, and an oral agent that produces no more than a 10% incidence of tremor. Suboptimal oral dosages in combination with maximal dosages of beta 2-agonist aerosol, with or without other bronchodilator drugs, are advisable for chronic therapy. An optimal risk/benefit ratio with broxaterol therapy will probably be achieved by using an aerosol-oral combination. Thus, broxaterol, a new beta 2-agent, should be studied further to determine its value in chronic bronchospastic disorders.