Haematology

Question 1

Iron replacement

Answer 1

E.g. ferrous fumarate, ferrous sulfate, iron sucrose (parental therapy)
Use: treatment or prophylaxis of iron deficiency anaemia
MOA: replenish iron stores (essential for erythropoiesis and the synthesis of the harm component of Hb, giving RBCs ability to carry O2). Iron is best absorbed in its ferrous state (Fe2+) in the duo- and jejunum, and its absorption is increased by stomach acid and dietary acids (vitamin C). Once absorbed, it is bound by transferrin, which transports it either to be used in the BM (erythropoiesis) or to be stored as ferritin (in the liver, reticuloendothelial system, BM, spleen, skeletal muscle).
Adverse effects: GI upset (nausea, epigastric pain, constipation, diarrhoea), bowels may turn black, irritation and hypersensitivity reactions (IV)
Cautions: oral iron may exacerbate bowel symptoms in those with IBD/diverticular disease/intestinal strictures. IV iron used in caution in those with atopic predisposition.
Interactions: may reduce absorption of levothyroxine and bisphosphonates.

Question 2

Hydroxycobalamin

Answer 2

Use: megaloblastic anaemia and subacute combined degeneration of the cord (as a result of B12 deficiency)
MOA: synthetic form of coalamin or vitamin B12

Question 3

Folic acid

Answer 3

Use: megaloblastic anaemia as a result of folate deficiency, and in T1 of pregnancy (reduce NTD risk)
MOA: synthetic form of folate or vitamin B9
Cautions: if co-existing B12 and folate deficiency, replace both simultaneously (replacing folate alone may be assoc. with progression of neurological manifestations of vitamin B12 deficiency)

Question 4

Darbepoetin

Answer 4

Use: symptomatic anaemia due to renal impairment
MOA: stimulates erythropoiesis by same as endogenous EPO
Adverse effects:
Cautions: CI in patients unable to receive VTE and uncontrolled HTN
Interactions: arthralgia, embolism, headache, HTN, influenza-like illness, skin reactions