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P A R T 2
Chemotherapeutic agents
occurs in the liver; caution should be used in individuals
with hepatic dysfunction.
Primaquine is readily absorbed and metabolised in
the liver. Excretion occurs primarily in the urine. Safety
for use during pregnancy has not been established.
Contraindications and cautions
Antimalarials are contraindicated in the presence of
known allergy to any of these drugs; liver disease or
alcoholism,
both because of the parasitic invasion of the
liver and because of the need for the hepatic metabolism
to prevent toxicity
; and breastfeeding
because the drugs
can enter breast milk and could be toxic to the infant.
Another method of feeding the baby should be used if
treatment is necessary. These drugs should be avoided
during pregnancy
because they are associated with birth
defects.
With mefloquine, which is teratogenic in pre-
clinical studies, pregnancy should be avoided during and
for 2 months after completion of therapy. Use caution
in people with retinal disease or damage
because many
of these drugs can affect vision and the retina, and the
likelihood of problems increases if the retina is already
damaged
; with psoriasis or porphyria
because of skin
damage
; or with damage to mucous membranes,
which
can occur as a result of the effects of the drug on
proteins and protein synthesis.
There have been some
genetic enzyme differences identified in various groups
that predispose them to adverse effects associated with
these drugs
.
See Box 12.4 for cultural considerations
and the use of some antimalarials.
Oesophageal ulceration has been associated with the
use of doxycycline. Therefore, it is important that doxy
cycline should be administered with adequate amounts
of fluid or food and the person should remain sitting
or standing for up to 2 hours afterwards to prevent the
possible development of oesophageal irritation.
Adverse effects
A number of adverse effects may be encountered with
the use of these antimalarial agents. Central nervous
system (CNS) effects include headache and dizziness.
Immune reaction effects related to the release of mero-
zoites include fever, shaking, chills and malaise. Nausea,
vomiting, dyspepsia and anorexia are associated with
direct effects of the drug on the GI tract and the effects
Two fixed-combination drugs are available for use in
the prevention and treatment of malaria. Combining
two different preparations in one drug may increase
compliance by reducing the number of pills a person has
to take, and it conforms to the treatment protocol of
taking drugs that affect the protozoa at different stages
of their life cycle.
Riamet
is a combination of artemether and
lumefantrine. It is indicated for treatment of
P. falciparum
malaria.
Riamet
is contraindicated in
the first trimester of pregnancy and women should be
advised to use barrier contraceptives while taking it.
Breastfeeding should not commence for at least 4 weeks
after the last dose as little data exists on effects on the
infant.
Usual dosage, acute attack:
Adult and paediatric (>35 kg or >12 years): 6 doses of
4 tablets PO over 60 hours
Paediatric (5–35 kg and >3 months–12 years): 6 doses of
1–3 tablets PO over 60 hours
Malarone
and
Malarone Junior
combine atovaquone
and proguanil. They are indicated for the prevention
of
P. falciparum
malaria when chloroquine resistance
has been reported. They are used for the treatment of
uncomplicated
P. falciparum
malaria when mefloquine
has not proved successful, most likely because of
resistance. This combination should be used in
pregnancy and breastfeeding only if the benefit clearly
outweighs the potential risk to the fetus or neonate.
Usual dosage, acute attack:
Adult: 4 tablets PO as a single daily dose for
3 consecutive days
Paediatric (11–20 kg): 1 adult tablet PO daily for
3 consecutive days
Paediatric (21–30 kg): 2 adult tablets PO daily as a single
daily dose for 3 consecutive days
Paediatric (31–40 kg): 3 adult tablets PO daily as a
single daily dose for 3 consecutive days
Paediatric (>40 kg): 4 adult tablets PO daily as a single
daily dose for 3 consecutive days
Prevention:
Adult: 1 tablet PO daily
Paediatric (11–20 kg): 1 junior tablet PO daily
Paediatric (21–30 kg): 2 junior tablets PO daily
Paediatric (31–40 kg): 3 junior tablets PO daily
Paediatric (>40 kg): 1 adult tablet PO daily
Prevention should start 1–2 days before exposure
and continue throughout plus 7 days after leaving the
area.
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BOX 12.2
Combination drugs used for malaria
prevention and treatment
With the emergence of chloroquine-resistant strains
of
Plasmodium
, the use of quinine and another of the
following antibiotics is recommended as a combination
therapy for the treatment of uncomplicated or severe
malaria caused by strains with unknown resistance:
doxycycline: Adult and paediatric (>8 yrs): 100 mg/
day PO for 2 days prior to entering malaria region,
continuing during stay and for 2 weeks after leaving.
tetracycline: 250 mg PO for 7 days for adults; 25 mg/kg
per day PO in divided doses q.i.d. for 7 days for
children
See Chapter 9 for a full discussion of these drugs.
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BOX 12.3
Antibiotics used to treat malaria
