C H A P T E R 1 4
Antineoplastic agents
199
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Alkylating agents affect cellular RNA, DNA or other
cellular proteins, are cell cycle non-specific, and are
most effective against slow-growing tumours.
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People receiving alkylating agents may experience
alopecia, nausea and vomiting and need to be
monitored for bone marrow suppression and CNS
toxicity.
KEY POINTS
■
■
Monitor the results of laboratory tests such as full
blood count (FBC) with differential
to identify
possible bone marrow suppression and toxic
drug effects
; and renal and liver function tests to
determine need for
possible dose adjustment and
identify toxic drug effects
.
Implementation with rationale
■
■
Arrange for blood tests before, periodically during,
and for at least 3 weeks after therapy
to monitor
bone marrow function to aid in determining the
need for a change in dose or discontinuation of the
drug
.
■
■
Administer medication according to scheduled
protocol and in combination with other drugs as
indicated
to improve effectiveness
.
■
■
Ensure that the person is well hydrated
to decrease
risk of renal toxicity
.
■
■
Protect the person from exposure to infection;
limit invasive procedures
when bone marrow
suppression limits the person’s immune/
inflammatory responses
.
■
■
Provide small, frequent meals, frequent mouth care
and dietary consultation as appropriate
to maintain
nutrition when GI effects are severe
. Anticipate the
need for antiemetics if necessary. (See Box 14.5.)
■
■
Arrange for proper head covering at extremes of
temperature if alopecia occurs; a wig, scarf or hat
is important for maintaining body temperature
.
If alopecia is an anticipated effect of drug therapy,
advise the person to obtain a wig or head covering
before the condition occurs
to promote self-esteem
and a positive body image
.
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■
Provide teaching about the following:
–– Follow the appropriate dosage regimen, including
dates to return for further doses.
–– Cover the head at extremes of temperature.
–– Maintain nutrition if GI effects are severe.
–– Avoid exposure to infection.
–– Plan for appropriate rest periods because fatigue
and weakness are common effects of the drugs.
–– Consult with a healthcare provider, if
appropriate, due to the possibility of impaired
fertility.
–– Use barrier contraceptives
to reduce the risk of
pregnancy during therapy
.
Evaluation
■
■
Monitor response to the drug (alleviation of cancer
being treated, palliation of signs and symptoms of
cancer).
■
■
Monitor for adverse effects (bone marrow
suppression, GI toxicity, neurotoxicity, alopecia,
renal or hepatic dysfunction).
■
■
Evaluate the effectiveness of the teaching plan
(person can name the drug, dosage, possible
adverse effects to watch for and specific measures
to help avoid adverse effects).
Antineoplastic drugs can directly stimulate the
chemoreceptor trigger zone (CTZ) in the medulla to
induce nausea and vomiting. These drugs also cause
cell death, which releases many toxins into the system,
which in turn stimulate the CTZ. Because people
expect nausea and vomiting with the administration of
antineoplastic agents, the higher cortical centres of the
brain can stimulate the CTZ to induce vomiting just at
the thought of the chemotherapy.
A variety of antiemetic agents have been used in
the course of antineoplastic therapy. Sometimes a
combination of drugs is most helpful. It should also be
remembered that an accepting environment, plenty of
comfort measures (e.g. environmental control, mouth
care, ice chips), and support for the person can help
to decrease the discomfort associated with the emetic
effects of these drugs. Antihistamines to decrease
secretions and corticosteroids to relieve inflammation
are useful as adjunctive therapies.
Drugs that are known to help in treating
antineoplastic chemotherapy–induced nausea and
vomiting include the following:
• Ondansetron (
Zofran
), granisetron (
Kytril
) and
palonosetron (
Aloxi
) block serotonin receptors in the
CTZ and are among the most effective antiemetics,
especially if combined with a corticosteroid such as
dexamethasone. The usual dosage is three 0.15-mg/
kg doses IV or 8 mg PO three times a day starting
30 minutes before chemotherapy (ondansetron) or
10 mg/kg IV or 1 mg PO twice a day (granisetron),
or 0.25 mg IV over 30 seconds, starting 30 minutes
before chemotherapy (palonosetron).
• Aprepitant (
Emend
) blocks human substance
P/neurokinin 1 receptors in the CNS, blocking the
nausea and vomiting caused by severely emetogenic
antineoplastic drugs without effects on dopamine
or serotonin. The usual dosage is 125 mg PO 1 hour
before chemotherapy (day one) and 80 mg PO once
daily in the morning on days two and three; given in
combination with 12 mg dexamethasone PO on day
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BOX 14.5
Antiemetics and cancer chemotherapy
