C H A P T E R 4 9
Drugs used to treat anaemias
787
■■
Iron products are used to replace iron in cases of
iron-deficiency anaemia, which can occur because of
deficient iron intake or because of blood loss leading
to lower iron levels.
■■
Iron products commonly cause constipation, nausea,
green stools and GI upset.
■■
Iron toxicity can cause severe CNS toxicity, coma
and even death because high iron levels are very toxic
to nerve cell membranes.
KEY POINTS
AGENTS USED FOR OTHER ANAEMIAS
This section discusses treatment for megaloblastic
anaemias and sickle cell anaemia. Table 49.3 gives a
complete list of agents.
A
gents
for megaloblastic anaemias
Megaloblastic anaemia is treated with folic acid and
vitamin B
12
. Folate deficiencies usually occur secondary
to increased demand (as in pregnancy or growth spurts);
as a result of absorption problems in the small intestine;
because of drugs that cause folate deficiencies; or sec-
ondary to the malnutrition of alcoholism. Vitamin B
12
deficiencies can result from poor diet or increased
demand, but the usual cause is lack of intrinsic factor
in the stomach, which is necessary for absorption. The
drugs are usually given together to ensure that the
problem is addressed and the blood cells can be formed
properly (see Table 49.3). Folic acid derivatives include
folic acid (
Fefol
) and calcium folinate (
Leucovorin
)
.
B
12
includes hydroxocobalamin (
Hydroxo-B
12
, Neo-B
12
),
co-methylcobalamin (
Methylcobalamin
) and cyanoco-
balamin (generic)
.
Therapeutic actions and indications
Folic acid and vitamin B
12
are essential for cell growth
and division and for the production of a strong stroma
Evaluation
■
■
Monitor response to the drug (alleviation of
anaemia).
■
■
Monitor for adverse effects (GI upset and reaction,
CNS toxicity, coma).
■
■
Monitor the effectiveness of comfort measures and
compliance with the regimen.
■
■
Evaluate the effectiveness of the teaching plan
(person can name drug, dosage, adverse effects
to watch for and specific measures to avoid them;
person understands the importance of continued
follow-up).
TABLE 49.3
DRUGS IN FOCUS Agents used for other anaemias
Drug name
Dosage/route
Usual indications
Agents for megaloblastic anaemias
Folic acid derivatives
calcium folinate
(Leucovorin)
1 mg/day IM for replacement; 12–15 g/m
2
PO,
then 10 g/m
2
PO q 6 hours for 72 hours for
rescue
Replacement therapy and treatment
of megaloblastic anaemia; used as
“leucovorin rescue” after chemotherapy,
allowing non-cancerous cells to survive
the chemotherapy; used with fluorouracil
for palliative treatment of colorectal
cancer (see Chapter 14)
folic acid (Ferro-F-tab,
FGF)
1 mg/day PO, IM, SC or IV
Replacement therapy and treatment of
megaloblastic anaemia
Vitamin B
12
co-methylcobalamin
(Methylcobalamin)
2 mL slow IM
Replacement therapy: treatment of
pernicious anaemia
cyanocobalamin (generic)
Adult: 5 mg/day deep IM
Neonatal: 1 mg/day IM
Replacement therapy; treatment of
megaloblastic anaemia, pernicious anaemia
hydroxocobalamin
(Hydroxo-B12,
Neo-B12)
250–1000 mcg IM alternate days × 1–2 weeks,
then 250 mcg/week IM
Replacement therapy; treatment of
megaloblastic anaemia, pernicious anaemia
Agent for sickle cell anaemia
hydroxyurea (Hydrea)
Initially 15 mg/kg per day PO as a single dose;
increase by 5 mg/kg per day every 12 weeks
to a maximum dose of 35 mg/kg per day PO
Reduction of frequency of painful crises and
to decrease the need for blood transfusions
in adults with sickle cell anaemia
