C H A P T E R 3 0
Adrenergic agonists
467
■■
Most of the
b
2
-specific adrenergic agonists are used to
manage and treat asthma, bronchospasm and other
obstructive pulmonary diseases.
■■
Isoprenaline, a non-specific
β
-specific adrenergic
agent, is used for its sympathomimetic effects to treat
shock, cardiac standstill and certain arrhythmias
when used systemically; it is especially effective in the
treatment of heart block in transplanted hearts.
■■
Because of its many adverse effects, isoprenaline is
reserved for use in emergency situations that do not
respond to other, safer therapies.
CHAPTER SUMMARY
■■
Adrenergic agonists, also called sympathomimetics,
are drugs that mimic the effects of the sympathetic
nervous system (SNS) and are used to stimulate the
adrenergic receptors within the SNS. The adverse
effects associated with these drugs are usually also a
result of sympathetic stimulation.
■■
Adrenergic agonists include
a
- and
b
-adrenergic
agonists, which stimulate both types of adrenergic
KEY POINTS
receptors in the SNS, and
a
-specific and
b
-specific
adrenergic agonists, which stimulate only
a
- or only
b
-receptors, respectively.
■■
a
-specific adrenergic agonists, such as phenylephrine
and clonidine, stimulate only the
a
-receptors within
the SNS. Clonidine specifically stimulates
a
2
-receptors
and is used to treat hypertension because its action
blocks the release of noradrenaline from nerve axons.
■■
Many of the
b
2
-specific adrenergic agonists are used
to manage and treat asthma, bronchospasm and
other obstructive pulmonary diseases.
■■
Isoprenaline, a non-specific
b
-specific adrenergic,
is used to treat shock, cardiac standstill and
certain arrhythmias when used systemically; it is
especially effective in the treatment of heart block in
transplanted hearts.
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ONLINE RESOURCES
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BIBLIOGRAPHY
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■
■
Use minimal doses of isoprenaline needed to
achieve desired effects
to prevent adverse effects
and maintain safety.
■
■
Arrange for supportive care and comfort measures,
including rest and environmental control,
to relieve
CNS effects
; provide analgesics for headache
and safety measures if CNS effects occur
to
provide comfort and prevent injury
; and avoid
overhydration
to prevent pulmonary oedema.
■
■
Provide thorough teaching, including drug name,
dosage and frequency of administration; rationale
for administration; monitoring required; anticipated
adverse effects, measures to reduce these and
warning signs of problems to report immediately.
Evaluation
■
■
Monitor response to the drug (improvement in
condition being treated, stabilisation of blood
pressure, prevention of preterm labour, cardiac
stimulation).
■
■
Monitor for adverse effects (GI upset, CNS
changes, respiratory problems).
■
■
Evaluate the effectiveness of the teaching plan
(person can name drug, dosage, adverse effects to
watch for and specific measures to reduce them).
■
■
Monitor the effectiveness of comfort measures and
compliance with the regimen.
