Review of Pharmacology - 9E (2015)

Review of Pharmacology
8. Ans. (b) It results in decrease in reticulocyte count (Ref: Katzung 10/e p537-538;KDT 6/e p592)
• Erythropoietin is a hematopoietic growth factor that is normally produced by the kidneys.
• Normally, there is an inverse relationship between serum erythropoietin levels and hemoglobin levels. When
Hb decreases and anemia becomes more severe, serum erythropoietin level increases exponentially. But,
anemia due to chronic renal failure is an exception to this inverse relationship. In CRF, erythropoietin is not
produced, that results in anemia. So, exogenous erythropoietin will markedely improve anemia in CRF patients
whereas there is less likelihood of response in other anemias.
• Erythropoietin consistently improves the hematocrit and Hb levels and usually eliminates the need of blood
transfusions in CRF patients.
• An increase in reticulocyte count is usually observed in 10 days and increase in hematocrit and Hb levels in
about 2-6 weeks.
Hematology
9. Ans. (b) Folic acid alone causes improvement of anemic symptoms but neurological dysfunction continues (Ref: Katzung
10/e p532; KDT 6/e p591)
• Vitamin B 12
is required for conversion of methionine to homocysteine and for formation of succinyl CoA from methylmalonyl
CoA.
• Deficiency of vitamin B 12
results in megaloblastic anemia, GI manifestations and neurological abnormalities (due to
demyelination).
• Folic acid alone will correct the symptoms of megaloblastic anemia but it does not prevent neurological abnormalities,
which continue to proceed.
• Neurological abnormalities manifests intially in the form of loss of posterior column sensations (vibration, proprioception
etc.), but later on can result in subacute combined degeneration of spinal cord.
10. Ans. (a) Neutropenia (Ref: Katzung’s 11/e p580-581)
• Filgrastim (G-CSF) and sargramostim (GM-CSF) are used to prevent or treat chemotherapy induced neutropenia.
• Erythropoietin is used to treat anemia associated with chronic renal failure and cancer chemotherapy.
• Oprelvekin (1L-11) is used to prevent and treat thrombocytopenia.
11. Ans. (b) Oral Deferiprone (Ref: KDT 6/e p868)
• Drug of choice for acute iron poisoning is desferrioxamine, however it has to be administered parenterally. It is not
effective by oral route.
• In beta thalassemia major, iron excess can result due to repeated blood transfusions and massive hemolysis. Chelating
agent has to be administered for long time in this case. Therefore, oral Deferiprone is preferred in this case.
12. Ans. (a) Duodenum and upper jejunum (Ref: KK Sharma 2007/675, Katzung 11/e p/571)
• Maximum iron absorption occurs in duodenum and proximal jejunum.
• Vitamin B 12
is absorbed in distal ileum whereas folic acid is absorbed in proximal jejunum.
13. Ans. (c) Erythropoietin (Ref: KDT 6/e p592)
Chronic renal failure may result in anemia due to deficient production of erythropoietin.
14. Ans. (a) Cannot be injected i.v. (Ref: KDT 6/e p586)
Iron sorbitol citrate should not be used i.v. because it may rapidly saturate the transferrin receptors and can result in high
concentrations of free iron.
15. Ans. (a) Conversion of malonic acid to succinic acid (Ref: KDT 6/e p588)
Conversion of malonic acid to succinic acid requires vitamin B 12
but not folate. This reaction is required for myelin formation
and deficiency of B 12
is responsible for demyelination.
16. Ans. (b) Counteracting toxicity of high dose methotrexate therapy (Ref: KDT 6/e p592)
• Prophylaxis of neural tube defects require treatment with folic acid.
• Methotrexate toxicity can be prevented by 5′-formyltetrahydrofolate (folinic acid).
• Pernicious anemia requires the therapy with vitamin B 12
.
• Anemia associated with chronic renal failure is treated with erythropoietin.
460
https://kat.cr/user/Blink99/