C H A P T E R 2 4
Antiparkinsonism agents
377
The combination of levodopa with vitamin B
6
or
with phenytoin may lead to decreased efficacy of the
levodopa (see Critical thinking scenario). Reduced effect
iveness of both drugs may also result if dopaminergics
are combined with dopamine antagonists. In addition,
people who take dopaminergics should be cautioned to
avoid over-the-counter vitamins; if such medications are
used, the person should be monitored closely because a
decrease in dopaminergic effectiveness can result.
Care considerations for
people receiving dopaminergic agents
Assessment: History and examination
■
■
Assess for contraindications or cautions:
any known allergies to these drugs t
o avoid
hypersensitivity reactions
; GI depression or
obstruction, urinary hesitancy or obstruction,
benign prostatic hypertrophy or glaucoma,
which may be exacerbated by these drugs
;
cardiac arrhythmias, hypertension or respiratory
disease,
which may be exacerbated by dopamine
receptor stimulation
;
current status of pregnancy
or breastfeeding,
which are cautions or
contraindications to use of the drug
; and renal or
hepatic dysfunction,
which could interfere with the
drug’s excretion or metabolism.
■
■
Perform a physical assessment
to determine
baseline status before beginning therapy, to
determine the effectiveness of drug therapy and to
monitor for any potential adverse effects.
■
■
Inspect the skin for evidence of skin lesions or
history of melanoma if the person is to receive
levodopa,
which could cause or exacerbate
melanoma
.
■
■
Assess for a history of prolonged QT interval and
obtain an electrocardiogram if apomorphine is to
be administered
to avoid further prolonged QT
interval and serious arrhythmias
.
■
■
Assess level of orientation and neurological status,
including affect, reflexes, bilateral grip strength,
gait, tremors and spasticity,
to evaluate any CNS
effects.
■
■
Auscultate lungs and assess respiratory status
to
evaluate for changes that could be exacerbated by
the drug’s effect.
■
■
Monitor pulse, blood pressure and cardiac output
to evaluate for possible adverse effects.
■
■
Auscultate bowel sounds to evaluate GI motility
to assess for adverse effects.
■
■
Assess urine output and palpate bladder
to
determine adequate bladder and renal function.
■
■
Monitor the results of laboratory tests, such as
liver and renal function studies,
to determine need
for possible dose adjustment
, and full blood count
(FBC) with differential
to evaluate for possible
bone marrow suppression.
Implementation with rationale
■
■
Arrange to decrease the dose of the drug if therapy
has been interrupted for any reason
to prevent
systemic dopaminergic effects.
■
■
Evaluate disease progress and signs and symptoms
periodically and record
for reference of disease
progress and drug response.
■
■
Give the drug with meals
to alleviate GI irritation
if GI upset is a problem.
■
■
Monitor bowel function and institute a bowel
program
if constipation is severe.
■
■
Ensure that the person voids before taking the drug
if urinary retention is a problem.
■
■
Monitor urinary output, palpate bladder and check
for residual urine
if urinary retention becomes a
problem.
■
■
Establish safety precautions if CNS or vision
changes occur
to prevent injury.
■
■
Monitor hepatic, renal and haematological tests
periodically during therapy
to detect early signs
of dysfunction and consider re-evaluation of drug
therapy.
■
■
Provide support services and comfort measures as
needed
to improve compliance.
■
■
Provide thorough teaching about topics such as
the drug name and prescribed dose, measures
to help avoid adverse effects, warning signs that
may indicate problems, and the need for periodic
monitoring and evaluation
to enhance knowledge
about drug therapy and to promote compliance.
■
■
Offer support and encouragement
to help the
person cope with the disease and drug regimen.
Evaluation
■
■
Monitor response to the drug (improvement in
signs and symptoms of Parkinson’s disease).
■
■
Monitor for adverse effects (CNS changes, urinary
retention, GI depression, tachycardia, increased
sweating, flushing).
■
■
Evaluate the effectiveness of the teaching plan
(person can give the drug name and dosage,
name possible adverse effects to watch for and
specific measures to prevent them and discuss the
importance of continued follow-up).
■
■
Monitor the effectiveness of support measures and
compliance with the regimen.
