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Dr. Arulmozhi Ramarajan,
Church of South India Hospital,
Bangalore.
Why intravenous iron?
Iron Deficiency Anemia has been in existence for centuries, and
oral iron therapy has failed to eradicate this very preventable
and treatable malady. Oral iron therapy is certainly very
appropriate and first line for most IDA patients, but a good
number of patients do not show the desired response because of
various reasons. Intravenous iron sucrose appears to have the
potential for eradicating IDA because it overcomes the problems
of compliance and absorption and has an excellent safety record.
It can dramatically reduce maternal morbidity and mortality,
promote better neuro-development and cognitive functions in the
newborn / infant, and improve the quality of life of women
overall.
What should be our target?
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To achieve a
hemoglobin level of not less than 11.0 g/dL;
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To provide sufficient
iron to maintain TSAT (transferrin saturation) ≥ 20% and
ferritin ≥ 100 ng/mL;
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To avoid iron
overload: think of non-IDA in non-responders;
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And, to avoid blood
transfusions!
It is important to note that when aggressive iron therapy
elicits poor response or no response, one may be dealing with
non-IDA. There is a possibility of iatrogenic iron overload in
these patients.
What is Intravenous Iron Sucrose?
Intravenous Iron Sucrose is a brown, sterile, aqueous complex of
polynuclear iron hydroxide in sucrose containing 20mg elemental
iron per ml. The product has no preservatives. Parenteral iron
bypasses the gut and circumvents the natural regulatory
mechanism to deliver non-protein-bound iron. Pharmacologic
parameters show that the administered iron disappears very
rapidly from the serum, insuring a rapid correction of IDA.
Since iron disappearance from the serum depends on the need for
iron in the iron stores and iron utilizing tissues of the body,
serum clearance of iron is expected to be more rapid in iron
deficient patients treated with iron sucrose as compared with
healthy individuals.
Iron sucrose is dissociated into iron and sucrose by the
reticuloendothelial system. Following a single dose of 100mg of
iron, iron uptake in bone marrow, liver & spleen is rapid,
followed by emergence of iron in circulating RBCs. The sucrose
component is eliminated mainly by urinary excretion, some of it
gets metabolized.
What are the common indications for IV Iron therapy?
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Moderate to severe
anemia in pregnancy
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Intolerance /
non-compliance to oral iron therapy.
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Failure of oral iron
therapy (no clinical or hematological improvement after 4 –
6 weeks of treatment and rise in Hb is < 2gms%)
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IDA in pregnancy, with
limited time to treat.
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Anemic women who
refuse / decline blood transfusion (Jehovah’s Witnesses).
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Those who are donating
large amounts of blood for autotransfusion programs
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Pregnancy in women
with chronic renal disease.
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Postpartum, especially
in those who have had significant blood loss at delivery.
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Those with a disorder
of the gastrointestinal tract, such as ulcerative colitis,
in which symptoms may be aggravated by oral iron therapy
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Those with anemia due
to chronic blood loss caused by AUB.
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Pre / post operative
correction of iron deficiency in women undergoing surgery.
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Those with
chemotherapy-induced anemia.
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Hemodialysis
associated blood loss and resulting negative iron balance.
How safe is IV iron? What are the side effects?
Intravenous iron sucrose is effective, safe, well tolerated. It
is labeled as a Category B drug in pregnancy. The side effects
profile is acceptable, with most of the reported side effects
being transient, mild, and not requiring any medical
intervention. The reported incidence of side effects is less
than 0.5%, with a maximum single dose of 200mg IV. Side effects
were a major concern with the previously used intravenous irons,
including the iron dextran complex. These have been largely
eliminated because the iron sucrose preparation is of small
molecular weight, and contains no synthetic polymers or
preservatives.
Reported side effects to IV iron sucrose include a transient
metallic taste, pain at injection site, nausea, lethargy, light
headedness and facial flushing. Vasovagal ‘reactions’ are
uncommon, and resolve within 30 minutes. Rare sensitivity
reactions including anaphylactic shock, requiring medical
intervention and discontinuance of drug have been reported.
However, these are quite rare, the reported incidence being
about 3 – 4 / million / year.
IV iron use within current guidelines is safe.
When NOT to give intravenous iron sucrose:
How much IV iron to give?
Dose calculation:
Iron deficit in mg = Pre-pregnancy body wt in kg x Hb deficit in
gms / dl x 2.4 + 500 mg for stores.
The total deficit is given in divided doses of 200mg per dose,
with a spacing of at least 48 hours between doses.
How to give?
Administration of IV iron sucrose is simple. No test dose
required for intravenous iron sucrose. It can be given on an OP
basis. Following IV administration the serum iron concentration
increases and reaches a peak after 4 hours after administration
and decreased to base line after 48 hrs. Positron emission
tomography studies have shown that the infused iron is
immediately incorporated into the bone marrow. Therefore it is
safe to repeat the dose after 48 hours.
Maximum recommended dose per sitting is 200mg. Intravenous iron
sucrose may be given undiluted, as an IV push, over a period of
4 – 5 minutes, using a butterfly needle. This method gives
enormous benefits including cost and time savings. The same may
be diluted in normal saline and given as an IV infusion over 20
minutes. There is no significant difference in the therapeutic
benefit / side effect profile between the two methods of
administration.
How to assess the efficacy of IV iron sucrose?
Response to therapy is noticed as early as Day 7 of treatment.
Patients report a feeling of wellness, and blood test shows
reticulocytosis, rise in hemoglobin % and improvement in red
cell indices.
What’s the message?
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IV iron is safe, sure
and corrects IDA.
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Hb of 10gms or less is
indication enough to give IV iron
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Advice on a nutritious
iron rich diet is important
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Deworming &
antimalarial treatment need to be given
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Cost reduction can be
achieved by using a butterfly needle & direct undiluted IV
iron push over 2 – 5 minutes as per guidelines.
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Adding proteins,
vitamins including folate & minerals to the recipe improves
outcome.
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It is important to
check response to therapy.
Conclusion:
Although treatment of iron deficiency certainly is not confined
to patients with kidney disease, the majority of published
evidence on IV iron therapy resides in the nephrology
literature.
A Cochrane review on treatments for iron-deficiency anemia
during pregnancy stated that despite the high incidence and
burden of disease associated with this condition, there is a
paucity of good quality studies evaluating clinical maternal and
neonatal effects of iron administration in pregnant women with
anemia. Daily oral iron therapy improves hematological indices
but is associated with gastrointestinal adverse effects.
Intramuscular and intravenous iron therapy enhances
hematological response, compared with oral iron, but there are
concerns regarding possible important adverse effects. The
authors noted that large, good quality studies that evaluate
clinical outcomes including adverse effects are needed (Reveiz
et al, 2007).
Take every opportunity to correct iron deficiency: Adolescents,
(why wait to diagnose anemia in pregnancy?) pre-pregnancy,
pregnancy, post partum, AUB, those awaiting surgery, those who
decline blood transfusion.
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