C H A P T E R 2 6
Opioids, opioid antagonists and antimigraine agents
407
constipation and biliary spasm may occur as a result of
CTZ stimulation and the negative effects on GI motility.
Light-headedness, dizziness, psychoses, anxiety, fear,
hallucinations and impaired mental processes may occur
as a result of the activation of CNS opioid receptors in the
cerebrum, limbic system and hypothalamus. GU effects,
including ureteral spasm, urinary retention, hesitancy
and loss of libido, may be related to direct receptor stim-
ulation or to CNS activation of sympathetic pathways.
Although sweating and dependence, both physical and
psychological, are possible, their occurrence is consid-
ered less likely than with opioid agonists.
Clinically important drug–drug interactions
When opioid agonists–antagonists, like opioid agonists,
are given with barbiturate general anaesthetics, the
likelihood of respiratory depression, hypotension, and
sedation or coma increases. If this combination cannot
be avoided, individuals should be monitored closely and
appropriate supportive measures taken.
Use of opioid agonists–antagonists in people who
have previously received any opioid puts these indi-
viduals at risk for increased adverse effects, including
respiratory depression. When such a sequence of drugs
is used, individuals will require support and monitoring.
Care considerations for people
receiving opioid agonists and opioid
agonists–antagonists
Assessment: History and examination
■
■
Assess for contraindications or cautions:
any known allergies to these drugs
to avoid
hypersensitivity reactions
; respiratory dysfunction,
which may be exacerbated by the respiratory
depression caused by these drugs
; MI or CAD,
which could be exacerbated by the effects of these
drugs
; renal or hepatic dysfunction,
which might
interfere with drug metabolism or excretion
;
current status of pregnancy and breastfeeding,
which require cautious use of the drugs
; diarrhoea
caused by toxic poisons
because depression of
GI activity could lead to increased absorption
and toxicity
; and after biliary surgery or surgical
anastomoses
because of the adverse effects
associated with slowed GI activity due to opioids.
■
■
Perform a pain assessment with the person
to establish baseline status and evaluate the
effectiveness of drug therapy.
■
■
Perform a physical assessment
to establish baseline
status before beginning therapy, determine drug
effectiveness and evaluate for any potential
adverse effects.
■
■
Assess orientation, affect, reflexes and pupil size
to evaluate any CNS effects
; monitor respiratory
rate and auscultate lungs for adventitious sounds
to evaluate respiratory effects.
■
■
Monitor pulse, blood pressure and cardiac output
to evaluate for cardiac effects.
■
■
Palpate abdomen for distension and auscultate
bowel sounds
to monitor for GI effects
; assess
urine output and palpate for bladder distension
to evaluate for GU effects.
■
■
Monitor the results of laboratory tests such as liver
and renal function tests
to determine the need for
possible dose adjustment and identify toxic drug
effects
.
Implementation with rationale
■
■
Perform baseline and periodic pain assessments
to monitor drug effectiveness and provide
appropriate changes in pain management protocol
as needed
.
■
■
Have an opioid antagonist and equipment
for assisted ventilation readily available when
administering the drug IV
to provide support in
case of severe reaction.
■
■
Monitor injection sites for irritation and
extravasation
to provide appropriate supportive
care if needed
.
■
■
Monitor timing of analgesic doses.
Prompt
administration may provide a more acceptable
level of analgesia and lead to quicker resolution
of the pain.
■
■
Use extreme caution when injecting these drugs
into any body area that has poor perfusion or
shock
because absorption may be delayed, and
after repeated doses an excessive amount is
absorbed all at once.
■
■
Use additional measures to relieve pain (e.g. back
rubs, stress reduction, hot packs, ice packs)
to
increase the effectiveness of the opioid being given
and reduce pain.
■
■
Monitor respiratory status before beginning
therapy and periodically during therapy
to monitor
for potential respiratory depression.
■
■
Institute comfort and safety measures, such as
side rails and assistance with ambulation,
to
ensure safety
; bowel program as needed
to treat
constipation
; environmental controls
to decrease
stimulation
; and small, frequent meals
to relieve
GI distress if GI upset is severe.
■
■
Reassure individuals that the risk of addiction is
minimal.
Most people who receive these drugs
for medical reasons do not develop dependency
syndromes.
■
■
Offer support and encouragement
to help the
person cope with the drug regimen.
