Pharmacological agents to treat asthma

Question 1

Importance

Answer 1

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

Question 2

‘Preventer’ drugs or anti-inflammatory agents

Answer 2

These medications are directed toward 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 SABA >3 times/wk.

Question 3

Corticosteroids

Answer 3

Inhaled: Types—

1. beclomethasone
2. budesonide
3. ciclesonide
4. 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

Question 4

Sodium cromoglycate (SCG)

Answer 4

This mast cell stabiliser, available as;

• dry capsules for inhalation
• metered dose aerosols
• nebuliser solution

The availability of the metered aerosol and spacer has helped the use of SCG in the management of asthma in children.

Question 5

Nedocromil sodium

Answer 5

A newer non-steroid cromolyn metered aerosol.

The initial dose is 2 inhalations qid.

Question 6

Leukotriene antagonists

Answer 6

These new agents, which include;

• montelukast
• zafirlukast

are very useful for seasonal asthma and aspirin-sensitive asthma

and may reduce the need for inhaled steroids.

Question 7

‘Reliever’ drugs or bronchodilators

Answer 7

The three groups of bronchodilators are:

1. β2-adrenoceptor agonists (β2-agonists)
2. Methylxanthines—theophylline derivatives
3. Anticholinergics

All pts should be prescribed a reliever.

Question 8

B2-agonists

Answer 8

Oral administration of B2-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 (SABA).

The new longer acting agents (LABA) include;

• salmeterol
• vilanterol
• eformoterol.

LABA should only be used in combination, not as monotherapy.

Question 9

Combination therapy

Answer 9

Inhaled corticosteroids (ICS) + LABA

Rules: use for moderate–severe asthma

The different types should be used in different ways.

When stabilised, drop LABA component and return to ICS.

Question 10

Fixed dose combination medication:

Answer 10

fluticasone + salmeterol = Seretide

MDI: 50/25; 125/25; 250/25 mg

Dose: adults: 2 inhalations bd; children 4–12: 2 inhal 50/25 bd

Accuhaler: 100/50; 250/50; 500/50

Dose: adults: 1 inhal bd; children 4–12: 1 inhal 100/50 bd

budesonide + eformoterol = Symbicort

Turbuhaler: 100/6; 200/6; 400/12

Dose: 1–2 inhal bd, according to age and need children >12: 100/60 or 200/6

fluticasone + eformoteral = Flutiform (MDI)

fluticasone + vilanterol = Breo ellipta (dry powder for inhalation)

Answer 11