Negligible metabolic effects of long-term oral treatment with a new beta 2-agonist: broxaterol.

Drugs that stimulate adrenergic receptors are expected to affect glucose and lipid metabolism. Therefore, it was deemed to be of interest to assess whether the new selective beta 2-adrenoceptor agonist, broxaterol, exerts any metabolic effect. Broxaterol has been evaluated in 21 patients, 18 men and 3 women, aged 34 to 80 years, with a diagnosis of reversible obstructive airways disease. Broxaterol was administered orally at doses of 0.5 mg thrice daily for 1-12 months, according to an open design. In addition to metabolic parameters (plasma glucose, insulin, high and low density lipoprotein-cholesterol, triglycerides, free fatty acids, glycerol, sodium, potassium), arterial pH, partial arterial oxygen and carbon dioxide pressure, lung function tests--forced expiratory volume in one second (FEV1), maximum mid-expiratory flow (MMEF75-25) and specific airways conductance (SGaw)--heart rate and blood pressure were assessed at baseline and after 1, 2, 3, 4, 5, 6, 9, 12 months of treatment. No statistically significant change from baseline was observed in the levels of plasma glucose, cholesterol, triglycerides, or free fatty acids. Plasma levels of insulin, glycerol and sodium only increased in the first three months of treatment; a slight hypokalaemia was also observed during the same period. The bronchodilation (significant increase in FEV1, MMEF75-25, SGaw) was maintained throughout the study; no hospital admission was necessary. Tremor, palpitations and restlessness were reported in six patients; no significant changes in heart rate and blood pressure were observed. The data suggest that the metabolic effects of long-term treatment with oral broxaterol can be considered as very negligible.