Asthma

INTRODUCTION

Definition of good control of asthma

• Minimal symptoms during day and <2 days a week

• No nocturnal waking due to asthma

• No limitation of physical activity

• Minimal need for reliever medication

• No overuse of β₂-agonist

• No exacerbations

• No side effects of medication

• Normal lung function FEV₁ ± PEFR >80% predicted of best

PHARMACOLOGICAL AGENTS TO TREAT ASTHMA

It is useful to teach patients the concept of the ‘preventer’ and the ‘reliever’ for their asthma treatment.

‘Preventer’ drugs or anti-inflammatory agents

These medications are directed towards the underlying abnormalities, bronchial hyper-reactivity and associated airway inflammation. They are underused in practice.

Treatment with a preventer medication is recommended if asthma episodes >3/wk or those who use SAβ β A >3 times/wk.

Corticosteroids

Inhaled: Types—beclomethasone, budesonide, ciclesonide, fluticasone (long acting). Dose range: 400–1600 mcg (adults); aim to keep below 400 mcg (children), 1000 mcg (adults)

Note: Rinse mouth out with water and spit out after using inhaled steroids.

Oral

Prednisolone is used mainly for exacerbations, given with the usual inhaled corticosteroids and bronchodilators.

Dose: up to 1 mg/kg/d for 1–2 wks

Cromones: sodium cromoglycate (SCG)

This mast cell stabiliser is available as dry capsules for inhalation, metered dose aerosols or as a nebuliser solution. The availability of the metered aerosol and spacer has helped the use of SCG in the management of asthma in children.

Nedocromil sodium

A newer non-steroid cromolyn metered aerosol. The initial dose is 2 inhalations qid.

Leukotriene antagonists

These new agents, which include montelukast and zafirlukast, are very useful for seasonal asthma and aspirin-sensitive asthma and may reduce the need for inhaled steroids.

‘Reliever’ drugs or bronchodilators

The three groups of bronchodilators are:

• the β₂-adrenoceptor agonists (β₂-agonists)

• methylxanthines—theophylline derivatives

• anticholinergics

β₂-agonists Oral administration of β₂-agonists is rarely required. The inhaled drugs produce measurable bronchodilatation in 1–2 mins and peak effects by 10–20 mins. The traditional agents such as salbutamol and terbutaline are short-acting preparations (SAβA). All patients should be prescribed a reliever. The new longer-acting agents (LAβA) include salmeterol, vilanterol and eformoterol. LAβA should only ...