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P A R T 4
Drugs acting on the central and peripheral nervous systems
If TCAs are combined with sympathomimetics or
clonidine, the risk of arrhythmias and hypertension is
increased. This combination should be avoided, espe
cially in people with underlying cardiovascular disease.
The combination of TCAs with MAO inhibitors
leads to a risk of severe hyperpyretic crisis with severe
convulsions, hypertensive episodes and death. This com
bination should be avoided. Although TCAs and MAO
inhibitors have been used together in selected individuals
who do not respond to a single agent, the risk of severe
adverse effects is very high.
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Affect is a term that refers to the feelings that people
experience when they respond emotionally.
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Depression is an affective disorder characterised by
inappropriate sadness, despair and hopelessness.
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According to the biogenic amine theory, depression is
caused by a brain deficiency of the biogenic amines.
Antidepressant drugs are thought to raise the level of
the biogenic amines.
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Antidepressant discontinuation syndrome may
occur within 5 days of stopping treatment with
antidepressant drugs; symptoms are usually mild and
self-limiting (lasting for 1–2 weeks), but in some cases
may be severe.
KEY POINTS
Care considerations for
people receiving tricyclic antidepressants
Assessment: History and examination
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Assess for any known allergies to these drugs
to
avoid hypersensitivity reactions
; impaired liver or
kidney function,
which could alter metabolism and
excretion of the drug
; glaucoma, benign prostatic
hypertrophy, cardiac dysfunction, GI obstruction,
surgery or recent myocardial infarction,
all of
which could be exacerbated by the effects of the
drug
; and pregnancy or breastfeeding
to avoid
potential adverse effects on the fetus or baby
.
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Assess whether the person has a history of seizure
disorders or a history of psychiatric problems or
suicidal thoughts, or myelography within the past
24 hours or in the next 48 hours, or is taking
an MAO inhibitor,
to avoid potentially serious
adverse reactions.
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Assess temperature and weight; skin colour and
lesions; affect, orientation and reflexes; vision;
blood pressure, including orthostatic blood
pressure; pulse and perfusion; respiratory rate
and adventitious sounds; and bowel sounds
on abdominal examination.
This determines
baseline status before beginning therapy and
for any potential adverse effects.
Also obtain
an electrocardiogram, as well as renal and liver
function tests.
Implementation with rationale
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Limit drug access if the person is suicidal
to decrease the risk of overdose.
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Maintain the initial dose for 4 to 8 weeks
to evaluate the therapeutic effect.
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Administer parenteral forms of the drug only if
oral forms are not feasible or available; switch to
an oral form,
which is less toxic and associated
with fewer adverse effects
, as soon as possible.
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Administer a major portion of the dose at bedtime
if drowsiness and anticholinergic effects are severe
to decrease the risk of injury. Elderly people may
not be able to tolerate larger doses.
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Reduce dose if minor adverse effects occur, and
discontinue the drug slowly if major or potentially
life threatening adverse effects occur
to ensure
safety.
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Provide comfort measures
to help the person
tolerate drug effects.
These measures may include
voiding before dosing, instituting a bowel program
as needed, taking food with the drug if GI upset
is severe and environmental control (lighting,
temperature, stimuli).
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Provide thorough teaching, including drug name,
prescribed dosage, measures for avoidance of
adverse effects and warning signs that may indicate
possible problems. Instruct the person about
the need for periodic 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 diagnosis and the drug
regimen.
Evaluation
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Monitor response to the drug (alleviation of signs
and symptoms of depression).
■
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Monitor for adverse effects (sedation,
anticholinergic effects, hypotension, cardiac
arrhythmias, suicidal thoughts).
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Evaluate the effectiveness of the teaching plan
(person can give the drug name, dosage, possible
adverse effects to watch for, specific measures
to help avoid adverse effects and importance of
continued follow-up).
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Monitor the effectiveness of comfort measures and
compliance with the regimen.
