4.6 Problems due to Opioids Flashcards
A 48-year-old male attends the pre-anaesthetic clinic with a chronic use of high-dose opioids for low back pain.
a) Enumerate the long-term side effects and concerns with
opioids if used for non-cancer pain.
● Nausea, vomiting, dizziness, dry mouth, sedation —
usually patients become tolerant to these
over a period of time.
● Pruritus —
persists in long-term opioid intake.
● Constipation —
persists in long-term intake of opioids.
● Respiratory depression.
● Hallucinations, drowsiness.
● Endocrine and hormonal dysfunction —
influence on the hypothalamo-pituitary-adrenal axis
and hypothalamo-pituitary gonadal axis to
cause adrenal insufficiency and hypogonadism.
This can cause reduced libido, amenorrhoea, erectile dysfunction, depression and fatigue.
● Immunological —
immunomodulating effect leading to immune
suppression.
● Opioid-induced hyperalgesia.
● Tolerance, physical dependence and addiction
b) Define tolerance, physical dependence and addiction.
● Tolerance —
an increased dose of a drug is required
to achieve the same effect.
● Physical dependence —
if the drug is stopped or antagonised or its
dose is reduced there is a withdrawal syndrome
associated with it.
● Addiction —
addiction is characterised by a behaviour
that manifests as impaired control and
compulsive use of a drug associated
with its craving, despite the harm.
c) What is opioid-induced hyperalgesia (OIH)?
Opioid-induced hyperalgesia is a state of nociceptive
sensitisation caused, following the exposure to opioids.
It is a paradoxical phenomenon wherein
administration of an opioid can cause a
pro-nociceptive state in the nervous system.
d) What are the presenting features of OIH?
● Diffuse and widespread pain
all over the body
along with increased sensitivity.
● Pain does not respond
to the administration of
an increased dose of opioid.
e) How would you manage a patient with OIH?
● Identification of OIH and differentiating from
opioid tolerance and the
progression of the underlying disease process.
● Slow and gradual reduction in the
dose of opioids used for pain.
● The use of non-opioid strategies for pain management
f) What would be your substitute drug with the aim of reducing
opioids in this patient in a pain clinic?
● Buprenorphine (sublingual).
● Methadone (orally).
g) What are the aims and principles of substitution therapy in
such patients?
● To reduce the associated harm from the use of a problem drug.
● To prevent a withdrawal reaction from the problem drug, thereby providing stability.
● To reduce preoccupation and craving
associated with the problem drug.
