Inhaled Corticosteroids as Rescue Medication in Acute Severe Asthma

Gustavo J Rodrigo

Disclosures

Expert Rev Clin Immunol. 2008;4(6):723-729. 

In This Article

Abstract and Introduction

Abstract

Systemic corticosteroids (CS) should be considered as first-line treatment for acute asthma exacerbations, especially severe exacerbations. They may sometimes require a few hours or more to achieve their maximum effect. This time delay observed between administration of CS and improvement in lung function or hospital admissions is consistent with the belief that these effects of CS, involving the modification of gene expression, occur with a time lag of hours or days (genomic effect). On the other hand, CS also have effects initiated by specific interactions with membrane-bound or cytoplasmic receptors for CS, or nonspecific interactions with the cell membrane, with a much more rapid response (seconds or minutes; nongenomic effect). This review analyzes the clinical evidence regarding the use of inhaled CS in acute asthma patients, according to the characteristics of the nongenomic effect, and presents a proposal for the use of inhaled CS as a rescue medication in the emergency-department setting.

Introduction

All patients with asthma may experience exacerbations or attacks, characterized by a progressive increase in shortness of breath, cough, wheezing or chest tightness, and a decrease in expiratory airflow.[40] Acute asthma is a medical emergency that must be diagnosed and treated urgently, and its intensity ranges from mild episodes, which may even go unnoticed by the patient, to extremely serious episodes that place a patient's life at risk and may even result in death (fatal or near-fatal asthma).[1] The severity of the asthma exacerbations determines the treatment administered and the goals of treatment can be summarized as maintenance of adequate arterial oxygen saturation with supplemental oxygen, relief of airflow obstruction with repetitive administration of rapid-acting inhaled bronchodilators (β-agonists and anticholinergics) and reduction of airway inflammation and prevention of future relapses with early administration of systemic corticosteroids (CS).[2]

Systemic CS should be considered as a first-line treatment for acute asthma exacerbations, especially severe exacerbations.[3,4,40] These agents are extremely effective at reducing the airway inflammation present in virtually all asthmatics. Despite controversy regarding their efficacy, route of delivery and dosage, data summarized in two systematic reviews suggest that:

  • Systemic CS require more than 4-6 h to improve pulmonary function and reduce hospitalizations;

  • Intravenous and oral CS appear to have equivalent effects in most patients with acute asthma;

  • While precise dose-response relationships are not well described, there is a tendency toward greater and more rapid improvement in pulmonary function with medium (parenteral hydrocortisone 100 mg every 6 h) and high (200 mg every 6 h) doses, although these effects are likely to plateau at very high dosing, without additional benefit.[3,4]

The time delay observed between administration and improvement in lung function or hospital admissions is consistent with the belief that these effects of CS result from changes in gene transcription and altered protein synthesis (genomic effect).[5]

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