C H A P T E R 2 5
Muscle relaxants
393
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Centrally-acting skeletal muscle relaxants are used
to relieve the effects of muscle spasm. Dantrolene,
a direct-acting skeletal muscle relaxant, is used
to control spasticity and prevent malignant
hyperthermia.
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Botulinum toxin type A is used to improve the
appearance of moderate to severe glabellar lines and
to treat cervical dystonia, severe primary axillary
hyperhidrosis, and strabismus and blepharospasm
associated with dystonia.
KEY POINTS
Implementation with rationale
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Discontinue the drug at any sign of liver
dysfunction.
Early diagnosis of liver damage may
prevent permanent dysfunction. Arrange for the
drug to be discontinued if signs of liver damage
appear.
A prodrome, with nausea, anorexia and
fatigue, is present in 60% of people with evidence
of hepatic injury.
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Do not administer botulinum toxins into any area
with an active infection
because of the risk of
exacerbation of the infection.
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Monitor intravenous access sites for potential
extravasation
because the drug is alkaline and very
irritating to tissues.
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Institute other supportive measures (e.g.
ventilation, anticonvulsants as needed, cooling
blankets) for the treatment of malignant
hyperthermia
to support the person through the
reaction.
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Periodically discontinue the drug for 2 to 4 days
to monitor therapeutic effectiveness.
A clinical
impression of exacerbation of spasticity indicates
a positive therapeutic effect and justifies continued
use of the drug.
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Establish a therapeutic goal before beginning
oral therapy (e.g. to gain or enhance the ability
to engage in a therapeutic exercise program; to
use braces; to accomplish transfer manoeuvres)
to
promote compliance and a sense of success with
therapy.
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Discontinue the drug if diarrhoea becomes severe
to prevent dehydration and electrolyte imbalance.
The drug may be restarted at a lower dose.
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Provide thorough teaching, including drug name,
prescribed dosage, measures for avoidance of
adverse effects, warning signs that may indicate
possible problems and the need for monitoring
and evaluation
to enhance knowledge about drug
therapy and to promote compliance.
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Offer support and encouragement to help the
person cope with the drug regimen.
Evaluation
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Monitor response to the drug (improvement in
spasticity, improvement in movement and activities;
improvement in dystonia, facial lines, sweating
with botulinum toxins).
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Monitor for adverse effects (CNS changes,
diarrhoea, liver toxicity, urinary urgency).
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Evaluate the effectiveness of the teaching plan
(person can give the drug name and dosage,
possible adverse effects to watch for and
specific measures to prevent adverse effects, and
therapeutic goals).
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Monitor the effectiveness of comfort measures and
compliance with the regimen.
CRITICAL THINKING SCENARIO
Skeletal muscle relaxants for cerebral palsy
THE SITUATION
L.G. is 26 years old. He was diagnosed with cerebral palsy
shortly after his birth. He lives in the community in a group
home with six other affected people. Two adult caregivers
provide supervision. In the past few months, L.G.’s spasticity
has progressed severely, making it impossible for him to
carry on his daily activities without extensive assistance.
Following a clinical evaluation, his healthcare team
suggests trying a course of dantrolene therapy. After
learning about the risks of dantrolene-related hepatic
dysfunction, L.G. decides that the benefits of dantrolene
therapy are more important to him than the risks of
hepatotoxicity. The healthcare team proceeds with a
complete physical examination, including liver enzyme
analysis. Therapy begins and a clinic staff member
schedules L.G. for a visit by a community nurse in 4 days.
CRITICAL THINKING
What basic principles must be included in the care
plan for L.G. for the visiting nurses?
Think about the
importance of including the adult caregivers in any
teaching or evaluation programs. Consider specific
problems that could develop that L.G. would be unable
to handle on his own.
