Sympathomimetics in acute severe asthma: inhaled or parenteral, nebulizer or spacer?

Abstract

It is accepted today that all patients with acute asthma should be treated with a sympathomimetic, irrespective of previous therapy. This short review addresses the question of the optimal mode of administration of these drugs in acute severe asthma. Inhaled sympathomimetics are as effective as subcutaneous adrenaline, or intravenous salbutamol or terbutaline, and, as they produce fewer side-effects, are recommended as the best mode of administration. However, self-medication with a ready to use subcutaneous preparation may be indicated in those patients prone to very abrupt attacks. The conventional mode of inhalation therapy in acute asthma is nebulization, but equally effective bronchodilatation may be obtained with metered-dose inhalers combined with valved spacers. Tachypnoeic patients unable to perform a conventional inhalation manoeuvre can use one-way valve inhalation devices with repeated tidal breaths. Finally, sequential or even continuous inhalation techniques have recently been advocated, particularly in patients with impending respiratory failure.

High doses of sympathomimetics in severe bronchial asthma

“…Whatever the explanation, the clinical and functional improvement is dose-related. As emphasized by NosEDA and YERNAULT [1], the dose delivered by the inhaler is 10-20 times higher than that delivered by the nebulizer.…”

“…What is the explanation for the fai lure of low doses of beta-agonists and the success of higher ones? The authors of this review favour an inadequate mode of administration in some patients, and severe inflammation of the airway in others [1]. Even if we accept that a large proportion of asthmatic patients do not use inhalers correctly, it is hard to dismiss others, who have certainly learned how to use these devices.…”

“…In a short but excellent review published in a previous issue of the Journal, NosEDA and YERNAULT [1] present a thorough and updated analysis, and new concepts on the treatment of acute severe asthma by beta-agonists. The route of administration of the drugs, as well as the doses and procedure are carefully presented and discussed.…”