Broxaterol (Z.1170), a New Oral &lt;i&gt;β&lt;/i&gt;&lt;sub&gt;2&lt;/sub&gt;-Agonist Compared with Salbutamol

The effects on exercise tolerance after acute administration of β₂-agonists were investigated in 11 patients with partly reversible chronic airway obstruction after 400 μg of salbutamol (S) given intravenously (i.v.) and after 400 μg i.v. of a new selective β₂-agonist, broxaterol (B), by a cardiopulmonary incremental exercise test. At rest, while VE increased in respect to basal conditions (C) after S (from 13.3 ± 2.2 to 14.4 ± 2.8 l/min;p < 0.05) and after B (from 13.6 ± 3.1 to 15.5 ± 3.61/min; p < 0.05), VO₂, VCO₂ and VO₂/HR showed no substantial variations. A small, not significant reduction of PaO₂ was observed both after S (from 82.7 ± 11.7 to 79.1 ± 16.7 mm Hg) and B (from 81.6 ± 10.5 to 78.0 ± 11.0 mm Hg). The maximum workload increased neither after S (from 67.5 ± 39.1 to 66.6 ± 37.0 W) nor after B (from 65.7 ± 39.3 to 60.0 ± 35.8 W). At peak of exercise, VO₂, VCO₂ and VO₂/HR did not change after S and B as compared with C, whereas VE remained higher after both β₂-agonists throughout the effort. VO₂ at ventilatory anaerobic threshold (AT) was significantly greater either after S (from 744 ± 378 to 815 ± 302 ml/min; p < 0.05) and after B (from 756 ± 290 to 842 ± 292 ml/min; p < 0.05). The PaO₂ increase shown by these patients during effort was greater after β₂-agonists administration, ΔPaO₂ from rest to peak of exercise amounting to 14.9 ± 14.3 vs. 7.8 ± 8.2 mm Hg after Sand to 17.8 ± 15.1 vs. 8.8 ± 10.9 mm Hg after B, in respect to relative baseline (p < 0.05). We conclude that β₂-agonists, when given acutely, do not improve exercise tolerance in patients with reversible chronic airflow obstruction, although these drugs can induce a small increment of ventilatory AT. In addition, arterial blood gases do not deteriorate at rest and are better preserved during exercise after β₂-agonists.

Section: Introductionmentioning

confidence: 99%

Ineffectiveness of Intravenous β2-Agonists on Improving Exercise Tolerance in Patients with Reversible Chronic Airway Obstruction

Malerba

Boni²,

Tantucci³

et al. 1996

“…An other study compared only one dose of each drug, and showed that an 8 times higher dose of salbutamol gave the same bronchodilation as broxaterol [7], How ever, the present study is the only one which has been performed with cumula tively increasing doses of the drugs. This study showed a considerable increase of heart rate with oral treatment of both broxaterol and salbutamol.…”

Section: Discussionmentioning

confidence: 56%

“…This study showed a considerable increase of heart rate with oral treatment of both broxaterol and salbutamol. Earlier studies have also shown effects on heart rate, with higher doses of broxaterol, mainly 0.5 mg, similarto 4 mg salbutamol, also indicating that the clinical selectivity for p2-adrenoreceptors are the same for the two drugs [6][7][8],…”

Section: Discussionmentioning

confidence: 70%

Broxaterol, a New β2-Adrenoceptor Agonist Compared to Salbutamol in Asthmatics, Oral and Inhalation Treatment

Sigvaldasson¹,

Skoogh²,

Svedmyr³

1989

Two double-blind, double-dummy, randomized, crossover studies were performed in 8 asthmatic patients to evaluate β₂-adrenoceptor selectivity and potency of broxaterol compared to salbutamol. By oral route, a study with cumulatively increasing doses (total dose broxaterol 1.675 mg and salbutamol 26 mg) showed that as a bronchodilator broxaterol was 12–16 times more potent than salbutamol. The same potency difference was seen for an increase of heart rate and decrease of diastolic blood pressure, indicating that the clinical selectivity for β₂-adrenoceptors is equal for the two drugs. One study with cumulatively increasing doses of broxaterol and salbutamol (total dose 1.5 mg for both) showed that with the inhaled route, broxaterol was somewhat less potent than salbutamol with respect to bronchodilation. Side effects, increase of heart rate and tremor were considerably less pronounced by the inhaled route as compared to the same bronchodilatory effect given by the oral route.

“…Recently, in patients with reversible airway obstruction Perruchoud et al [13] reported no significant difference between the effects of 0.5 mg broxaterol and those of 4 mg salbutamol, both orally adminis tered, and they underlined the good toler ance of the two drugs. Perruchoud's re sults confirm a previous report of Rampulla et al [1] and Blasi and Pezza [2].…”

Section: Discussionmentioning

confidence: 99%

Early Bronchodilating Effect of a New Oral Beta-2-Receptor Agonist (Broxaterol) in Bronchial Asthma

Chetta

Garavaldi²,

Cuomo³

et al. 1988

In order to determine the bronchodilating activity and safety of two beta-2-receptor agonists, broxaterol and procaterol, compared with a placebo, 12 patients with reversible airway obstruction were tested in a double-blind cross-over study. The drugs were administered orally and the dosage of broxaterol was 0.5 mg, that of procaterol 0.05 mg.Measurements of forced expiratory volume in 1 s (FEV₁), heart rate and blood pressure were performed before and 30, 60, 120, 240, 360, and 480 min after each treatment. Both drugs produced bronchodilation but broxaterol was statistically 30 min faster in producing this effect than procaterol (p < 0.05). Moreover this effect for both drugs persisted significantly for up to 480 min compared with the effect of the placebo (p < 0.005). There were no significant side effects with either drug. Heart rate and blood pressure did not show any changes in clinical significance for broxaterol or procaterol. In our study, broxaterol showed a faster bronchodilating effect than procaterol, and tolerance was the same for both drugs.