Anemias and Hematinic Agents

Question 1

what is anemia?

Answer 1

the most common blood disorder- a defect in RBC formation or function
lack of tissue oxygenation

Question 2

what are the different types of anemia?

Answer 2

nutritional anemias
anemias due to blood loss
anemias due to chronic renal failure (decreased erythropoietin)
hemolytic anemia- oxidative damage- in G6PDH deficient patients
sickle cell anemia

Question 3

what are the nutritional anemias?

Answer 3

microcytic anemia and macrocytic anemias

Question 4

what is the cause of microcytic anemia

Answer 4

relative lack of iron

RBCs are relatively small, pale

Question 5

what is the normal iron metabolism?

Answer 5

iron is highly conserved by the body- no specific mechanism for eliminating iron
normally, we ingest iron and solubilized by HCL in the gut and absorbed as Fe2+ (ferrous iron)
Fe3+ (ferric) is not readily absorbed
Fe2+ is absorbed, converted to Fe3+ by molecule transferrin
transferrin is carrier for iron throughout the body
transferrin increases during times of anemia
excess iron is bound to and stored as ferritin in the liver

Question 6

what are the probable etiology of iron deficiency?

Answer 6

decreased iron uptake- not enough iron in diet
decreased absorption- if hcl is low or GI dysfunctions
increased iron requirement- in pregnancy, during periods of rapid body growth, px with renal disease
excess loss of iron due to chronic blood loss

Question 7

what is the primary cause of iron deficiency?

Answer 7

excess loss of iron due to chronic blood loss

Question 8

what is the drug of choice of microcytic anemia?

Answer 8

iron

FeSO4 is orally absorbed - Fe2+

Question 9

what are the routes of administration of iron?

Answer 9

oral- can cause gi upset

parenteral- severe deficiency- iron dextran-IM

Question 10

acute toxicity of iron

Answer 10

oral iron can be very toxic especially in children
lethal doses- as few as 10 tablets
nausea, severe abdominal pain- muscosal damage
drowsiness
cardiovascular collapse
convulsions and death

Question 11

what is the treatment of acute toxicity of iron?

Answer 11

a chelating agent- deferoxamine

Question 12

chronic toxicity of iron

Answer 12

too much iron is stored (hemachromatosis)

Question 13

what is the treatment of chronic toxicity of iron?

Answer 13

phlebotomy

Question 14

what is macrocytic anemia?

Answer 14

large RBC precursors- multilobed nuclei due to inhibition of DNA synthesis

Question 15

what is the macrocytic anemia?

Answer 15

folic acid deficiency anemia

Question 16

why is folic acid important?

Answer 16

folic acid is necessary for DNA replication

lack of folic acid can cause methionine deficiency

Question 17

what are the symptoms of folic acid deficiency?

Answer 17

macrocytic RBC precursors

Question 18

etiology of folic acid deficiencies?

Answer 18

intake deficiency
absorption is usually rapid
drugs can inhibit synthesis of the active form
increased requirements- infection, pregnancy, renal dialysis
folic acid deficiency in pregnancy can lead to neural tube defects in fetus

Question 19

therapy of folic acid deficiency

Answer 19

oral therapy is usually sufficient
parenteral therapy if there is an absorption abnormality
no contraindications, no toxicities
only indication– folic acid deficiency

Question 20

what is the function of vitamin b12?

Answer 20

b12 is essential for DNA synthesis and methionine synthesis

Question 21

what are the symptoms of b12 deficiency?

Answer 21

megaloblastic anemia
lack of methionine
cause decrease in myelin synthesis- neuronal damage- weakness, ataxia, spasticity; irreversible spinal cord damage

Question 22

what are the possible etiologies of b12 defiency?

Answer 22

insufficient intake is very rare
decreased absorption- most common cause due pt may lack ability to make GIF (gastric intrinsic factor made by parietal cells- b12 requires GIF for absorption

Question 23

what happens if patient lacks ability to make GIF?

Answer 23

pernicious anemia

fatal if not treated

Question 24

what are the pharmacologic treatment of b12 deficiency not due to lack of GIF?

Answer 24

oral administration

Question 25

what is the pharmacologic treatment of pernicious anemia?

Answer 25

b12 must be given injection

Question 26

what is shot gun therapy?

Answer 26

pernicious anemia looks like macrocytic anemia- thus give folic acid as treatment- appears to be treated but still have neuronal damage from pernicious anemia
need accurate diagnosis- give b12

Question 27

drugs that treat anemias due to chronic renal failure or chemotherapy?

Answer 27

epoietin alfa
darbepoietin
peginesatide

Question 28

what are the toxicities of epoietin alfa, darbepoietin, peginesatide?

Answer 28

due to an excess of RBC-> increase BP, increase clotting, myocardial infarction, stroke

Question 29

what is hemolytic anemia caused by?

Answer 29

abnormal lysis of rbc (broken down too readily)

Question 30

what is the treatment of hemolytic anemia?

Answer 30

iron is generally not useful

erythropoietin may be useful

Question 31

what is sickle cell anemia?

Answer 31

abnormal flow properties of RBC- RBC gets stuck in small blood vessels
causes severe joint pain

Question 32

what is used to treat sickle cell anemia?

Answer 32

hydroxyurea

Question 33

how does hydroxyurea work?

Answer 33

increase formation of fetal hemoglobin, which does not sickle

Question 34

what are the side effects of hydroxyurea?

Answer 34

mutagenic, pregnancy category D