Home' Australian Pharmacist : Australian Pharmacist May 2013 Contents Australian Pharmacist May 2013 I ©Pharmaceutical Society of Australia Ltd. 49
Continuing Professional Development
COUNSELLING IN PRACTICE
Aperients are essential for all patients
prescribed an opioid and the pharmacist
can reinforce this when presented with
a prescription for one. The pharmacist
should initially recommend acombination
of a stimulant laxative with a stool
softener (e.g. docusate with senna).
In resistant cases, an osmotic laxative
(e.g. polyethylene glycol) may be
The incidence of respiratory depression is
often dose-related and can be anticipated
in patients with a high sedation score
(see Table 1). Patients who have trouble
staying awake (sedation score of
2 or 3) are likely to present with early
respiratory depression and require urgent
Some rarer side effects such as itching or
flushing may be intolerable. Under these
circumstances, morphine is unsuitable
and other medicines will be substituted.
How e ective is the medicine likely
The onset of action of morphine products
vary according to the route by which
they are administered. Intravenous
administration has the fasted onset
of action with a peak effect of around
10 to 15 minutes. Immediate-release
oral liquid has a peak onset of about an
hour. This will be important to clarify,
particularly with the first prescription.
Because of its short duration of action,
controlled-release preparations of
morphine are imperative to provide a
sustained analgesic effect.
Cancer pain is commonly multidimensional
and may have neuropathic or psychosocial
elements to it.3 Consequently, management
of pain may require a number of
concomitant therapies to establish
satisfactory pain control. Depending upon
the factors contributing to pain, other
adjuvant therapies such as benzodiazepines
and antiepileptic agents may be helpful
to complement the work of the opioid.
Management should include ongoing
evaluation of a range of outcomes,
including function, symptom control and
Good pain control requires good
communication between patients,
carers and healthcare professionals.
immediate-release opioids given as
needed for breakthrough pain.
Where predictable episodes of
breakthrough pain exist (also known as
incident pain) immediate-release opioids
may also be used pre-emptively.
Does this mean my mother is about
Morphine has been misrepresented
as a medicine that is held in reserve
for the last days of life and this may
provide an inappropriate barrier to its
use. People also wrongly worry that
morphine will hasten death.8 In practice,
the introduction of opioids early in the
cancer setting allows rapid symptom
control, which has a direct impact of
improving the patient's ability to do the
things they enjoy. Concerns such as these
should be addressed immediately.
What are the side e ects?
Side effects should be anticipated for all
medicines. Cautious dose titration coupled
with attentive monitoring are vital in the
elderly as they are especially vulnerable
to opioid side effects.9 As morphine
is renally cleared, dose adjustment
should be performed in patients with a
calculated creatinine clearance of less
than 50 mL minute.10 In practice, this
will include most patients. Chronic use
should only be avoided in patients with
significant renal dysfunction (e.g. with a
calculated creatinine clearance of less than
10 mL minute).
Short-lived side effects that can present
in most people taking morphine include
nausea, somnolence and mental
clouding. These effects will often lessen
with continued treatment. The patient
should avoid driving or participating in
other activities requiring alertness until
any cognitive effects have dissipated.
The carer is in an excellent position to
monitor alertness and provide assistance
Some side effects, such as constipation,
are more long term in nature and will
require active pre-emptive management.
Milder analgesics (paracetamol or
non-steroidal anti-inflammatory drugs)
have been used to reduce the opioid
dose required but the evidence for this
is weak.5 Paracetamol is favoured over
non-steroidal anti-inflammatory drugs
because of a better side effect profile.
Sarah's mother, while using paracetamol,
has had uncontrolled pain. Both Margaret
and Sarah should be assured that opioids
are the most effective medicines available
for cancer pain, and by commencing
morphine early she will get relief from pain
and her quality of life will improve.
How long should the pain relief last?
Cancer pain is persistent and needs
around-the-clock management for
most successful outcomes. Utilising
a combination of controlled-release
medicines to provide background control
with extra doses of immediate-release
medicines for periods of breakthrough
pain is paramount. Occasionally, extra
doses may be employed for incident or
If the pain becomes unbearable,
can an extra dose be taken?
Changes in the way that pain is
experienced throughout the day should
be anticipated and is a reflection of
the natural fluctuation in how pain is
experienced amidst all of the patient's
usual activities. Breakthrough pain
is normal and should be expected.
Breakthrough doses are generally
calculated as 1/6 to 1/12 of the
background analgesic dose. Increases to
the background opioid dose are guided
by calculating the number of milligrams
delivered in total over a 24-hour period.
effects that can
present in most
and mental clouding. '
Table 1. Sedation score
0 -- wide awake
1 -- easy to rouse
2 -- easy to rouse, but cannot stay awake
3 -- difficult to rouse
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