This information paper outlines the current
position of leukotriene receptor antagonists (LTRAs) in the
treatment of children with asthma.
Registered indication and PBS
listing
Montelukast sodium (Singulair),
a specific inhibitor of the cysteinyl leukotriene
CysLT1-receptor, is registered for use in chronic
asthma prophylaxis and treatment in children aged 2
years and older.
Montelukast is reimbursed by the
Pharmaceutical Benefits Scheme as an alternative to
sodium cromoglycate or nedocromil sodium in
children. It is available on Streamlined Authority
as a first-line preventer medication in children
aged 2–14 years with frequent intermittent asthma or
mild persistent asthma, who are not taking any other
preventer medication.
When to consider LTRA therapy
As regular preventive therapy in
children with mild persistent asthma or frequent
intermittent asthma (as an alternative to low-dose
ICS or cromones)
As short-term therapy during
symptomatic episodes in children with intermittent
viral-induced asthma
In children with exercise-induced
asthma
There is less evidence to support
the use of LTRAs in children with moderate-to-severe
persistent asthma, who are more likely to benefit
from ICS therapy
The leukotrienes are a family of pro-inflammatory mediators that
play an important role in the pathophysiology of asthma.
Leukotrienes are derived from cell membranes and released
following activation of resident airway cells (mast cells) and
infiltrating cells (eosinophils and neutrophils). They are
involved in both early and late asthmatic airway responses to
allergen challenge. Leukotrienes are potent bronchoconstrictors
and also cause airway oedema, mucus secretion and recruitment of
eosinophils into the airway.
Leukotriene receptor antagonists bind to and
inhibit specific receptors within the airway. The action of
LTRAs differs from that of the cromones, sodium cromoglycate
(e.g. Intal) and nedocromil sodium (Tilade), which are believed
to exert their anti-inflammatory effects through mast cell
stabilisation and modulation of airway sensory nerve activation.
Two LTRAs are available in Australia:
zafirlukast and montelukast. Zafirlukast (Accolate) is
registered for use in asthma prophylaxis and treatment in
patients aged 12 years and over. Montelukast (Singulair)
is the only LTRA currently available for use in younger
children. Montelukast is an orally active, specific LTRA that
protects against early- and late-phase bronchoconstriction
response to allergen challenge, and against exercise-induced
bronchoconstriction.
