age under 55 years and low
alcohol intake were associated
with treatment failure in the acute
phase (first 24 hours) of treatment.
In contrast only female gender
was associated with treatment
failure in the delayed phase. In
both acute and delayed phases,
the number of risk factors present
was significantly associated with
likelihood of CINV.
There are a number of
recognised national and
international guidelines 7–9 that help
to determine the standard level
of antiemetic prophylaxis for a
specific chemotherapy treatment,
but the pharmacist can determine
patient-specific factors that are
present in an individual to decide
whether an increased level of
prophylaxis, or an alteration in
the prescription, is required.
The pharmacist should take
a medication history to determine
whether there are any significant
drug interactions that require an
alteration to therapy.
Aprepitant exhibits a number
of important potential interactions
due to its moderate inhibition of
the cytochrome P450 isoenzyme,
3A4 (CYP 3A4) and so particular
vigilance is required. 10 It has
been shown that aprepitant
interactions with chemotherapy
agents are generally not clinically
significant and do not require
specific action. 10 Netupitant is also
a moderate inhibitor of CYP 3A4
and there is an increased exposure
80 | 2018 | hospitalpharmacyeurope.com
to chemotherapy agents that are
substrates of CYP 3A4.
The medication history of a
patient might show that he/she
is already taking an antiemetic
for other purposes; for example,
cyclizine can be of value in
relieving vomiting and attacks of
vertigo associated with Menière’s
disease. This might require
alteration of standard antiemetic
prophylaxis to avoid duplication
and the risk of adverse effects.
Corticosteroids are integral to
many chemotherapy protocols
and, if this is the case, the steroid
should be omitted from the
antiemetic prophylaxis.
Comorbidities might affect
choice of antiemetic agent
and the pharmacist review
is essential to ensure that
appropriate amendments to the
standard regimens are made.
Corticosteroids can cause effects
on gluconeogenesis and should
be used with caution in patients
with diabetes. 11 This could mean
using smaller doses of steroid and
advising the patient to monitor
blood glucose levels more carefully
during chemotherapy treatment.
Discussions with the patient
can also highlight other issues that
affect the choice of antiemetic
therapy. The patient may have
swallowing difficulties and may
not be able to take standard
treatments in tablet or capsule
form. Alternatives include liquid
or dispersible preparations,