page196
Nebuliser
(or
respirator)
solutions
of
salbutamol
and
terbutaline are used for the treatment of
severe acute
asthma in hospital or in general practice. Patients with a
severe attack of asthma should preferably have oxygen
during nebulisation since beta
2
agonists can increase
arterial hypoxaemia. For the use of nebulisers in chronic
obstructive pulmonary disease,
see section 3.1.5.
The
dose given by nebuliser is substantially higher than that
given by inhaler.
Patients should therefore be warned
that it is dangerous to exceed the prescribed dose and
they should seek medical advice if they fail to respond to
the usual dose of the respirator solution, see also section
3.1.5.
Oral
Oral
preparations of beta
2
agonists may be used
by patients who cannot manage the inhaled route. They
are sometimes used for children and the elderly,
but
inhaled beta
2
agonists are more effective and have fewer
side-effects. The longer-acting oral preparations, includ-
ing bambuterol, may be of value in nocturnal asthma but
they have a limited role and inhaled long-acting beta
2
agonists are usually preferred.
Parenteral
Salbutamol
or
terbutaline can be given
intravenously
for
severe
or
life-threatening
acute
asthma;
patients
should be carefully monitored and
the dose adjusted according to response and heart
rate.
The regular use of beta
2
agonists by the subcuta-
neous route is not recommended since the evidence of
benefit is uncertain and it may be difficult to withdraw
such treatment once started. Beta
2
agonists may also be
given by intramuscular injection.
Children
Selective beta
2
agonists are useful
even in
children under the age of
18 months.
They are most
effective by the inhaled route;
a pressurised metered-
dose inhaler
should be used with a spacer device in
children under
5 years (see NICE guidance,
section
3.1.5).
A beta
2
agonist
may also be given by mouth
but
administration by inhalation is preferred;
a long-
acting inhaled beta
2
agonist may be used where appro-
priate
(see
Management
of
Chronic
Asthma
table,
p.
172).
In severe attacks nebulisation using a selective
beta
2
agonist
or
ipratropium is
advisable (see also
Management of Chronic Asthma table and Management
of Acute Asthma table,
p.
172 and p.
173).
Cautions
Beta
2
agonists should be used with caution in
hyperthyroidism,
cardiovascular
disease,
arrhythmias,
susceptibility to QT-interval
prolongation,
and hyper-
tension.
Beta
2
agonists should be used with caution in
diabetes—monitor blood glucose (risk of
ketoacidosis,
especially when beta
2
agonist
given intravenously).
Interactions: Appendix 1 (sympathomimetics,
beta
2
).
Hypokalaemia
Potentially serious hypokalaemia may
result from beta
2
agonist therapy.
Particular caution is
required in severe asthma,
because this effect may be
potentiated by concomitant treatment with theophylline
and its derivatives, corticosteroids, and diuretics, and by
hypoxia. Plasma-potassium concentration should there-
fore be monitored in severe asthma.
Side-effects
Side-effects of the beta
2
agonists include
fine tremor (particularly in the hands), nervous tension,
headache,
muscle cramps,
and palpitation.
Other side-
effects
include
tachycardia,
arrhythmias,
peripheral
vasodilation,
myocardial
ischaemia,
and disturbances
of
sleep and behaviour.
Paradoxical
bronchospasm
(occasionally
severe),
urticaria,
angioedema,
hypo-
tension,
and collapse have also been reported.
High
doses of
beta
2
agonists are associated with hypokal-
aemia (see Hypokalaemia above).
BAMBUTEROL HYDROCHLORIDE
Note
Bambuterol is a pro-drug of terbutaline
Indications
asthma and other conditions associated
with reversible airways obstruction
Cautions
see notes above
Hepatic impairment
avoid in severe impairment
Renal impairment
reduce initial dose by half if eGFR
less than 50 mL/minute/1.73m
2
Pregnancy
manufacturer advises avoid—no informa-
tion available;
see also p.
170
Breast-feeding
see p.
170
Side-effects
see notes above
Dose
. 20 mg once daily at bedtime if patient has previously
tolerated beta
2
agonists; other patients, initially 10 mg
once daily at bedtime, increased if necessary after 1–2
weeks to 20 mg once daily;
CHILD
not recommended
Bambec
c
(AstraZeneca) A
Tablets
,
both scored,
bambuterol hydrochloride
10 mg,
net price 28-tab pack = £12.05;
20 mg,
28-tab
pack = £13.14
FENOTEROL HYDROBROMIDE
Indications
reversible airways obstruction
Cautions
see notes above
Pregnancy
see p.
170
Breast-feeding
see p.
170
Side-effects
see notes above
Compound preparations
For compound preparation containing fenoterol, see
section 3.1.4
FORMOTEROL FUMARATE
(Eformoterol fumarate)
Indications
reversible airways obstruction (including
nocturnal asthma and prophylaxis of exercise-induced
bronchospasm) in patients requiring long-term regu-
lar bronchodilator therapy,
see also Management of
Chronic Asthma table,
p.
172;
chronic obstructive
pulmonary disease
Note
For use in asthma only in patients who regularly use an
inhaled corticosteroid, see notes above
Cautions
see notes above
Pregnancy
see p.
170
Breast-feeding
see p.
170
Side-effects
see notes above;
very rarely
QT- interval
prolongation;
taste disturbances,
nausea,
dizziness,
rash,
and pruritus also reported
Dose
. See under preparations below
Counselling
Advise patients not to exceed prescribed dose,
and to follow manufacturer’s directions; if a previously
effective dose of inhaled formoterol fails to provide adequate
relief, a doctor’s advice should be obtained as soon as
possible
Formoterol
(Non-proprietary) A
Dry powder for inhalation
,
formoterol fumarate
12 micrograms/metered inhalation,
net price 120-
dose unit = £23.75.
Counselling,
administration
Brands include
Easyhaler
c
Formoterol
Dose
by inhalation of powder,
asthma,
ADULT and CHILD over 6
years,
12 micrograms twice daily,
increased to 24 micr-
176
3.1.1 Adrenoceptor agonists
BNF 61
3
Respiratory system