page195
More severe croup (or
mild croup that
might
cause
complications)
calls
for
hospital
admission;
a single
dose of a corticosteroid (e.g.
dexamethasone 150 micr-
ograms/kg or prednisolone 1–2 mg/kg by mouth,
sec-
tion 6.3.2)
should be administered before transfer
to
hospital.
In hospital,
dexamethasone 150 micrograms/
kg (by mouth or by injection) or budesonide 2 mg (by
nebulisation,
section 3.2) will
often reduce symptoms;
the dose may need to be repeated after
12 hours if
necessary.
For severe croup not effectively controlled with cortico-
steroid treatment,
nebulised adrenaline solution 1 in
1000 (1 mg/mL)
should be given with close clinical
monitoring
in a
dose
of
400 micrograms/kg
(max.
5 mg) repeated after 30 minutes if necessary; the effects
of
nebulised adrenaline last
2–3 hours and the child
needs to be monitored carefully for recurrence of
the
obstruction.
3.1.1
Adrenoceptor agonists
(Sympathomimetics)
3.1.1.1
Selective beta
2
agonists
3.1.1.2
Other adrenoceptor agonists
The selective beta
2
agonists
(selective beta
2
-adreno-
ceptor
agonists,
selective
beta
2
stimulants)
(section
3.1.1.1) such as salbutamol or terbutaline are the safest
and
most
effective
short-acting
beta
2
agonists
for
asthma. Less selective beta
2
agonists such as ephedrine
(section 3.1.1.2) should be avoided whenever possible.
Adrenaline (epinephrine)
(which has both alpha-
and
beta-adrenoceptor
agonist
properties)
is
used in the
emergency management
of
allergic and anaphylactic
reactions
(section 3.4.3)
and in the management
of
croup (see above).
3.1.1.1
Selective beta
2
agonists
Selective beta
2
agonists
produce bronchodilation.
A
short-acting beta
2
agonist is used for immediate relief
of
asthma symptoms
while some long-acting beta
2
agonists
are
added to an inhaled corticosteroid in
patients requiring prophylactic treatment.
Management of Chronic Asthma table,
see p.
172
Management of Acute Asthma table,
see p.
173
Short-acting beta
2
agonists
Mild to moderate
symptoms of asthma respond rapidly to the inhalation
of a selective short-acting beta
2
agonist such as salbut-
amol
or
terbutaline.
If
beta
2
agonist
inhalation is
needed more often than once daily,
prophylactic treat-
ment should be considered, using a stepped approach as
outlined in the Management of
Chronic Asthma table,
p.
172.
Regular treatment with an inhaled short-acting
beta
2
agonist is less effective than ‘as required’
inhala-
tion and is not appropriate prophylactic treatment.
A short-acting beta
2
agonist inhaled immediately before
exertion reduces
exercise-induced asthma
;
however,
frequent
exercise-induced
asthma
probably
reflects
poor
overall
control
and calls
for
reassessment
of
asthma treatment.
Long-acting beta
2
agonists
Formoterol
(eformo-
terol) and salmeterol
are longer-acting beta
2
agonists
which are administered by inhalation.
They should be
used for asthma only in patients who regularly use an
inhaled corticosteroid (see CHM advice below).
They
have a role in the long-term control
of chronic asthma
(see Management of Chronic Asthma table, p.
172) and
they can be useful
in nocturnal
asthma.
Salmeterol
should not be used for the relief
of
an asthma attack;
it has a slower onset of
action than salbutamol
or ter-
butaline. Formoterol is licensed for short-term symptom
relief and for the prevention of exercise-induced bron-
chospasm; its speed of onset of action is similar to that
of salbutamol.
Combination inhalers that
contain a long-acting beta
2
agonist
and a corticosteroid (section 3.2)
ensure that
long-acting beta
2
agonists are not used without conco-
mitant
corticosteroids,
but
reduce
the
flexibility to
adjust the dose of each component.
CHM advice
To ensure safe use, the CHM has advised that for the
management
of
chronic asthma,
long-acting beta
2
agonists (formoterol and salmeterol) should:
.
be added only if
regular use of
standard-dose
inhaled corticosteroids
has
failed to control
asthma adequately;
.
not be initiated in patients with rapidly deterior-
ating asthma;
.
be introduced at
a low dose and the effect
properly
monitored before
considering
dose
increase;
.
be discontinued in the absence of benefit;
.
not
be used for
the relief
of
exercise-induced
asthma symptoms unless regular inhaled corti-
costeroids are also used;
.
be reviewed as clinically appropriate:
stepping
down therapy should be considered when good
long-term asthma control has been achieved.
A daily dose of 24 micrograms of formoterol should
be sufficient for the majority of children, particularly
for younger age-groups; higher doses should be used
rarely,
and only when control
is not maintained on
the lower dose.
Patients should be advised to report any deteriora-
tion in symptoms following initiation of
treatment
with a long-acting beta
2
agonist, see Management of
Chronic Asthma table,
p.
172.
Indacaterol
is
a
long-acting beta
2
agonist
recently
licensed for chronic obstructive pulmonary disease;
it
is not indicated for the relief of acute bronchospasm.
Inhalation
Pressurised-metered dose inhalers
are an
effective and convenient method of drug administration
in mild to moderate asthma.
A spacer device (section
3.1.5)
may improve drug delivery.
At
recommended
inhaled doses
the duration of
action of
salbutamol,
terbutaline and fenoterol
is about 3 to 5 hours and for
salmeterol
and formoterol
12 hours.
The dose,
the
frequency,
and the maximum number of inhalations in
24 hours of the beta
2
agonist should be stated explicitly
to the patient.
The patient
should be advised to seek
medical
advice when the prescribed dose of
beta
2
agonist fails to provide the usual degree of symptomatic
relief because this usually indicates a worsening of the
asthma and the patient may require a prophylactic drug
such as an inhaled corticosteroid (see Management of
Chronic Asthma table,
p.
172).
BNF 61
3.1.1 Adrenoceptor agonists
175
3
Respiratory system