摘要：

Synopsis Salbutamol (albuterol) is a β2-selective adrenoceptor agonist which accounts for its pronounced bronchodilatory, cardiac, uterine and metabolic effects. During the intervening years since salbutamol was first reviewed in the Journal (1971), it has become extensively used in the treatment of reversible obstructive airways disease. Numerous studies in this disease (including severe acute, childhood and exercise-induced asthma) have confirmed the bronchodilatory efficacy of salbutamol, and it has been shown to be at least as effective as most of the currently available bronchodilators, if not more effective. The onset of maximum effect of salbutamol is dependent on the formulation used and the route by which it is administered. In most patients inhaled salbutamol is a first-line therapy, since it offers rapid bronchodilation, usually relieving bronchospasm within minutes. Although oral salbutamol has often proved to be less efficacious than the inhaled formulation, it still affords clinically significant bronchodilation, and it is particularly useful in those patients unable to coordinate the use of inhalers. Parenteral formulations of salbutamol are generally reserved for the treatment of severe attacks of bronchospasm and they are one of the treatments of choice in these life-threatening situations. Studies of the concomitant use of salbutamol and other agents such as anticholinergics, methylxanthines and beclomethasone dipropionate have usually shown a complementary response in the majority of patients, as might be expected from the different mechanisms of action of these groups of drugs. Salbutamol is generally well tolerated and any side effects observed are a predictable extension of its pharmacology. Since the frequency of side effects is dose related, and therefore dependent on the route of administration, it is not surprising that they are much more common following intravenous and oral rather than inhalation therapy. Tremor, tachycardia and hypokalaemia are the most frequently reported adverse effects. After nearly 20 years of use, salbutamol is well established as a 'first-choice' treatment in reversible obstructive airways disease. Indeed, throughout this time many new bronchodilatory agents have been studied but none have proved more effective. Clinical evaluation of salbutamol in the treatment of premature labour, hyperkalaemia and cardiac failure awaits further studies, although to date some encouraging results have been reported. Pharmacodynamic Studies Salbutamol is a β2-selective adrenoceptor agonist which has demonstrated considerable bronchodilatory effects. In studies in healthy volunteers, inhaled salbutamol caused a rapid and significant bronchodilation by reducing bronchomotor tone in both the large and small airways, as reflected by increases in sGaw, FEV1, FEF25–75, FEF50, FEV3, FEF75–88 and FEF75, and effectively inhibited histamine-induced bronchospasm. As would be expected, the bronchodilatory effects of salbutamol are greatly diminished following coadministration of non-selective β-blockers such as propranolol, betaxolol and tertatolol. The selective β-blocker atenolol had no such effect. Lower doses of inhaled salbutamol are required to bring about maximum bronchodilation in normal volunteers than in asthmatic patients. Although salbutamol has effective antitussive properties, its clinical application in this area requires further investigation. In common with other β2-adrenoceptor agonists, salbutamol demonstrated vasodilatory and inotropic effects in healthy volunteers, and in patients with reversible obstructive airways disease or cardiovascular disease, particularly after intravenous administration. However, the clinical efficacy of salbutamol in the treatment of heart failure remains to be established. Intravenous salbutamol causes a marked reduction in uterine tonicity in women suffering from primary dysmenorrhoea, and this was associated with pain relief in pregnancy. Furthermore, salbutamol by intravenous infusion reduced uteroplacental blood flow by 18 to

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