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P A R T 5
Drugs acting on the autonomic nervous system
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Beta-blockers are drugs used to block the beta-
receptors within the SNS. These drugs are used for
a wide range of conditions, including hypertension,
stage fright, migraines, angina and essential tremors.
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Non-selective blockade of all beta-receptors results in
a loss of the reflex bronchodilation that occurs with
sympathetic stimulation. This limits the use of these
drugs in individuals who smoke or have allergic or
seasonal rhinitis, asthma or COPD.
KEY POINTS
myocardium to catecholamines, and severe
reactions could occur.
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Continuously monitor any individual receiving
an IV form of these drugs
to avert serious
complications caused by rapid sympathetic
blockade.
■
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Monitor blood pressure, pulse, rhythm and cardiac
output regularly
to evaluate drug effectiveness
and to monitor for changes that may indicate
a need to adjust dose or discontinue the drug if
cardiovascular effects are severe.
■
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Arrange for supportive care and comfort measures
(rest, environmental control, other measures)
to
relieve CNS effects
; institute safety measures if
CNS effects occur
to prevent injury;
provide small,
frequent meals and mouth care
to help relieve the
discomfort of GI effects
; establish a daily activity
program, spacing activities
to help the person deal
with activity intolerance
.
■
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Offer support and encouragement
to help the
person deal with the drug regimen.
■
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Provide thorough teaching, including drug name,
dose and schedule of administration; use of
drug with food or meals, if appropriate; possible
adverse effects and measures to prevent them;
warning signs to report; safety measures, such
as changing position slowly, avoiding driving or
using hazardous machinery, and pacing activities;
and the need for follow-up evaluation and
possible changes in dose to achieve therapeutic
effectiveness,
to enhance knowledge about drug
therapy and to promote compliance.
Evaluation
■
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Monitor response to the drug (lowering of
blood pressure, decrease in anginal episodes,
improvement in condition being treated).
■
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Monitor for adverse effects (GI upset, CNS
changes, respiratory problems, CV effects, loss
of libido and impotence).
■
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Evaluate the effectiveness of the teaching plan
(person can name drug, dosage, adverse effects to
watch for and specific measures to avoid them).
■
■
Monitor the effectiveness of comfort measures and
compliance with the regimen.
CRITICAL THINKING SCENARIO
Non-selective beta-blockers (propranolol)
THE SITUATION
M.R., a 59-year-old man, has been seen several times
complaining of tremor in his hands that eventually made it
very difficult for him to work as a computer programmer.
A diagnosis of essential tremor was made, and he was
prescribed propranolol (
Inderal
) 40 mg twice daily. M.R. had
good effects with the drug and had no further problems
until the following June, when acute respiratory distress
developed while he was picnicking in a state park with his
family. On the way to the emergency room, he suffered
an apparent respiratory arrest. He was admitted to the
hospital and placed in the respiratory intensive care unit.
It was found that M.R. had a history of hay fever and allergic
rhinitis during the pollen season but had never experienced
such a severe reaction.
CRITICAL THINKING
Why did M.R. have such a severe reaction? What appropriate
measures should be taken to ensure that M.R. recovers
fully and does not re-experience this event?
What sort of support will M.R. and his family need after
going through such a frightening experience? Think
about the children who may have witnessed the
respiratory arrest and how they should be reassured,
depending on their ages.
Think about the support M.R.’s
wife may need and the fear that may now be associated
with M.R.’s condition. M.R. has been taking propranolol
for several months and needs to decide whether he should
continue the drug with modifications to his lifestyle or the
addition of other drugs to deal with his respiratory issues.
What kind of teaching program will need to be developed
to help M.R. deal with this drug, and its potential adverse
effects?
