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sulfadoxine

Sulfadoxine is a long-acting sulfonamide antimicrobial agent used primarily in combination with pyrimethamine for the treatment and prevention of malaria. It inhibits dihydropteroate synthase, an enzyme in the parasite folate synthesis pathway, thereby blocking DNA synthesis. When paired with pyrimethamine, which inhibits dihydrofolate reductase, the combination produces a synergistic blockade of folate metabolism in Plasmodium species.

Clinical use centers on malaria treatment in regions with susceptible parasite strains and on malaria prevention

Pharmacokinetics and administration are oral, with a long half-life that supports single-dose preventive regimens but can

Safety and resistance: adverse effects can include hypersensitivity reactions, rash, and hematologic effects such as megaloblastic

strategies.
Sulfadoxine-pyrimethamine
(SP)
has
been
used
to
treat
uncomplicated
Plasmodium
falciparum
malaria
and,
in
some
areas,
P.
vivax
malaria.
Its
effectiveness
is
limited
by
widespread
resistance
due
to
mutations
in
parasite
dihydropteroate
synthase
(DHPS)
and
dihydrofolate
reductase
(DHFR).
SP
remains
a
component
of
intermittent
preventive
treatment
in
pregnancy
(IPTp)
and,
in
certain
guidelines,
intermittent
preventive
treatment
in
infants
(IPTi),
often
as
a
single-dose
regimen
administered
during
routine
antenatal
visits
or
vaccination
campaigns.
In
many
settings,
SP
is
no
longer
preferred
for
treating
malaria
due
to
resistance
and
is
restricted
to
preventive
uses
in
others.
contribute
to
selection
of
resistant
parasites.
It
is
usually
given
in
fixed-dose
combinations
with
pyrimethamine.
Metabolism
occurs
in
the
liver
with
renal
excretion.
anemia
related
to
folate
deficiency;
severe
reactions
are
rare
but
possible.
Folate
supplementation
can
diminish
the
efficacy
of
SP,
and
caution
is
advised
in
pregnancy,
sulfonamide
allergy,
or
folate-deficient
individuals.
Regulatory
status
varies
by
country,
with
many
guidelines
limiting
SP
to
preventive
use
in
malaria-endemic
areas
and
preferring
other
therapies
for
treatment
where
resistance
is
high.