C H A P T E R 1 2
Antiprotozoal agents
169
on CNS control of vomiting caused by the products of
cell death and protein changes. Hepatic dysfunction is
associated with the toxic effects of the drug on the liver
and the effects of the disease on the liver. Dermatological
effects include rash, pruritus and loss of hair associated
with changes in protein synthesis of the hair follicles.
Visual changes, including possible blindness related to
retinal damage from the drug, and ototoxicity related
to other nerve damage may occur.
Cinchonism
(nausea,
vomiting, tinnitus and vertigo) may occur with high
levels of hydroxychloroquine or primaquine.
Clinically important drug–drug interactions
The person who is receiving combinations of the quinine
derivatives and quinine is at increased risk for cardiac
toxicity and convulsions. Therefore, monitor the person
closely, checking drug levels and anticipating dose
adjustments as needed.
Potential for haemolytic crisis
People with glucose-6-phosphate dehydrogenase (G6PD)
deficiency—which is more likely to occur in Greeks,
Italians and other people of Mediterranean descent—
may experience a haemolytic crisis if they are taking the
antimalarial agent chloroquine or primaquine. People of
Greek, Italian or other Mediterranean ancestry should
be questioned about any history of potential G6PD
deficiency. If no history is known, the person should be
tested before any of these drugs are prescribed. If testing
is not possible and the drugs are needed, the person
should be monitored very closely and informed about
the potential need for hospitalisation and emergency
services.
Cultural considerations
BOX 12.4
Prototype summary: Hydroxychloroquine
Indications:
Treatment and prophylaxis of acute
attacks of malaria caused by susceptible strains
of
Plasmodium
; treatment of extraintestinal
amoebiasis.
Actions:
Inhibits protozoal reproduction and protein
synthesis.
Pharmacokinetics:
Route Onset
Peak
Duration
Oral
Varies
1–2 hours
1 week
T
1/2
:
70 to 120 hours; metabolised in the liver and
excreted in the urine.
Adverse effects:
Visual disturbances, retinal changes,
abdominal pain, nausea, vomiting, diarrhoea, skin
rashes.
Care considerations for
people receiving antimalarial agents
Assessment: History and examination
■
■
Assess for contraindications or cautions: history
of allergy to any of the antimalarials
to prevent
hypersensitivity reactions
; liver dysfunction
or alcoholism
that might interfere with the
metabolism and excretion of the drug
; porphyria
or psoriasis,
which could be exacerbated by the
drug effects
; retinal disease
that could increase the
visual disturbances associated with these drugs
;
and pregnancy and breastfeeding
because these
drugs could affect the fetus and could enter the
breast milk and be toxic to the infant
.
■
■
Perform a physical assessment
to establish baseline
data for assessment of the effectiveness of the
drug and the occurrence of any adverse effects
associated with drug therapy
. Assess CNS (reflexes
and muscle strength).
■
■
Perform ophthalmic and retinal examinations
and auditory screening
to determine the need for
cautious administration and to evaluate changes
that occur as a result of drug therapy
.
■
■
Assess the person’s liver function, including liver
function tests
to determine appropriateness of
therapy and to monitor for toxicity
.
■
■
Obtain blood culture to
identify the causative
Plasmodium
species
.
■
■
Inspect the skin closely for colour, temperature,
texture and evidence of lesions
to monitor for
adverse effects
.
Implementation with rationale
■
■
Arrange for appropriate culture and sensitivity tests
before beginning therapy
to ensure proper drug for
susceptible
Plasmodium
species
. Treatment may
begin before test results are known.
■
■
Administer the complete course of the drug
to get
the full beneficial effects
. Mark a calendar for
prophylactic doses. Use combination therapy as
indicated.
■
■
Monitor hepatic function and perform
ophthalmological examination before and
periodically during treatment
to ensure early
detection and prompt intervention with cessation
of drug if signs of failure or deteriorating vision
occur
.
■
■
Provide comfort and safety measures if CNS
effects occur (e.g. side rails and assistance with
ambulation if dizziness and weakness are present)
to prevent injury
. Provide oral hygiene and ready
access to bathroom facilities as needed
to cope
with GI effects
.
