C H A P T E R 4 9
Drugs used to treat anaemias
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BOX 49.1
Drug therapy across the lifespan
Drugs used to treat anaemias
CHILDREN
Proper nutrition should be established for children to
provide the essential elements needed for the formation of
RBCs.The cause of the anaemia should be determined to
avoid prolonged problems.
The safety and efficacy of epoetin alfa use have not
been established for children. If the drug is used, careful
dose calculation should be done based on weight and
age, and the child should be monitored very closely for
response, iron levels and nutrition.
Iron doses for replacement therapy are determined
by age. If a liquid solution is being used, the child should
drink it through a straw to avoid staining of the teeth.
Periodic blood counts should be performed; it may
take 4 to 6 months of oral therapy to reverse an iron
deficiency. Remember that iron can be toxic to children.
Iron supplements should be kept out of their reach and
administration monitored.
Maintenance doses for folic acid have been established
for children, based on age. Nutritional means should be
used to establish folic acid levels whenever possible.
Children with pernicious anaemia require a monthly
injection of vitamin B
12
; the nasal form has not been
approved for use with children.
ADULTS
The underlying cause of the anaemia should be
established and appropriate steps taken to reverse
the cause if possible. Adults receiving epoetin alfa
or darbepoetin alfa should be monitored closely for
response, for the need for iron or other RBC building
blocks, and for the possibility of development of pure red
cell aplasia.
Advertised heavily in the mass media, epoetin
is often requested by adults to help restore energy.
Careful teaching about the drug and how and why it is
administered may be needed.
Adults receiving iron replacement may experience
gastrointestinal upset and frequently experience
constipation. Appropriate measures to maintain bowel
function may be needed.
Adults also need to know that periodic blood tests will
be needed to evaluate response.
Adults being treated for pernicious anaemia may opt
for the nasal vitamin B
12
.These people need to receive
careful instructions about the proper administration of
the drug and should have nasal mucous membranes
evaluated periodically.
PREGNANCY AND BREASTFEEDING
Proper nutrition during pregnancy and breastfeeding is
often still not an adequate way to meet the increased
demands of those states. Prenatal vitamins contain iron
and folic acid and are usually prescribed for pregnant
women. Folic acid is known to be very important for the
development of the neural tube, and often women who are
considering becoming pregnant are encouraged to take
folic acid to build up levels for the planned pregnancy. Use
of epoetin alfa or darbepoetin alfa is not recommended
during pregnancy or breastfeeding because of the
potential for adverse effects on the fetus or baby. Iron
replacement is frequently needed postpartum to provide
the iron lost during delivery.The new mother should be
reminded to keep the drug out of the reach of children and
not to combine prescribed iron with an over-the-counter
preparation containing high levels of iron.
Women maintained on vitamin B
12
before pregnancy
should continue the treatment during pregnancy.
Increased doses may be needed due to changes associated
with the pregnancy.
OLDER ADULTS
Older adults may have nutritional problems related to
age and may lose more iron through cellular sloughing.
Older adults should be assessed for anaemia and possible
causes should be evaluated.
Replacement therapy in the older adult can cause the
same adverse effects as are seen in the younger person.
Bowel training programs may be needed to prevent severe
constipation.
Myeloid tissue of bone marrow
Haemocytoblasts
Mature erythrocytes
Circulation
Haemolysis: Liver, spleen, bone marrow
Bilirubin
Bile
Erythropoietin
Amino acids, lipids,
carbohydrates
Vitamin B
12
Folic acid
Iron
Epoetin alfa
Darbepoetin alfa
Methoxy polyethylene-glycol
erythropoietin beta
Macrocytic anaemia
Megaloblastic anaemia
Iron deficiency anaemia
120 days
Iron
Vitamin B
12
Reticulocytes
Hydroxocobalamin, cyanocobalamin
Folic acid, leucovorin
Iron preparations
FIGURE 49.2
Sites of action of drugs used to treat
anaemia.
