Drugs - Haematology

Question 1

Give 2 types of iron used in the treatment of iron deficiency anaemia?

Answer 1

Ferrous sulphate

Ferrous fumarate

Question 2

2 main functions of iron in RBCs?

Answer 2

• Essential for erythropoiesis (formation of new RBCs)
• Required for the synthesis of the haem component of Hb which gives RBCs the ability to carry O2

Question 3

In what form is iron best absorbed?

Answer 3

In its ferrous state (Fe2+)

Question 4

Where is iron absorbed?

Answer 4

in the duodenum and jejunum

Question 5

Once absorbed into the bloodstream, what is iron bound by?

Answer 5

Transferrin

Question 6

Function of transferrin?

Answer 6

Transferrin transports iron either to be used in the bone marrow for erythropoiesis or to be stored as ferritin in the liver, reticuloendothelial system, bone marrow, spleen and skeletal muscle

Question 7

How is iron stored?

Answer 7

As ferritin

Question 8

where does erythropoiesis occur?

Answer 8

Bone marrow

Question 9

Function of kidneys in erythropoiesis?

Answer 9

Produce erythropoietin (EPO), a hormone that signals your bone marrow to make red blood cells.

Question 10

Side effects of iron therapy?

Answer 10

• GI upset – nausea, epigastric pain, constipation & diarrhoea
• Patients may notice their bowel motions turn black on treatment
• IV iron can cause injection site irritation and hypersensitivity reactions (e.g. anaphylaxis)

Question 11

How can iron therapy affect stools?

Answer 11

Patients may notice their bowel motions turn black on treatment

Question 12

Contraindications for oral iron?

Answer 12

• Oral iron therapy may exacerbate bowel symptoms in those with intestinal disease – e.g. IBD, diverticular disease, intestinal strictures
• Unsafe swallow

Question 13

Contraindications for IV iron?

Answer 13

IV iron should be used with caution in those with an atopic predisposition due to risk of anaphylaxis

Question 14

Interactions of oral iron salts?

Answer 14

Oral iron salts can reduce the absorption of other drugs e.g. levothyroxine and bisphosphonates

Question 15

Why should iron therapy be stopped 7 days prior to a colonoscopy?

Answer 15

People with iron deficiency often require colonoscopy to investigate the cause of their anaemia. However, oral iron can turn stools black and sticky. This is problematic for visualizing the bowel during lower GI endoscopy as the sticky black stool coats the colon ad obscures the view

Question 16

What is hydroxocobalamin?

Answer 16

This is a synthetic form of cobalamin/vitamin B12

Question 17

What is thiamine?

Answer 17

Vitamin B1

Question 18

What is phytomenadione?

Answer 18

plant form of vitamin K

Question 19

What is thiamine used in the treatment/prevention of?

Answer 19

Used in the treatment and prevention of Wernicke’s encephalopathy and Korsakoff’s psychosis which are manifestations of severe thiamine deficiency

Question 20

What vitamin is folate?

Answer 20

B9

Question 21

What is folic acid?

Answer 21

synthetic form of folate/vitamin B9

Question 22

2 major indications for folic acid?

Answer 22

• Used in megaloblastic anaemia as a result of folate deficiency
• Used in the first trimester of pregnancy to reduce the risk of neural tube defects

Question 23

2 major indications for hydroxocobalamin?

Answer 23

Treatment of megaloblastic anaemia and subacute combined degeneration of the cord as a result of B12 deficiency

Question 24

2 major indications for phytomenadione?

Answer 24

• Recommended for all newborn babies to prevent vitamin K deficiency bleeding
• Used to reverse the anticoagulant effects of warfarin (prothrombin complex concentrate should also be given in cases of major bleeding)

Question 25

What type of blood product should be used in warfarin reversal?

Answer 25

prothrombin complex concentrate (PCC)

Question 26

How does phytomenadione reverse warfarin?

Answer 26

Phytomenadione reverses warfarin by providing a fresh supply of vitamin K for the synthesis of vitamin K dependent clotting factors by the liver

Question 27

When should folic acid be given in pregnancy?

Answer 27

1st trimester AND preconception period

Question 28

In patients with co-existing B12 and folate deficiency, why should you replace both vitamins simultaneously?

Answer 28

Replacing folate alone may be associated with the progression of neurological manifestations of vitamin B12 deficiency (major concern is risk of provoking subacute combined degeneration of the cord)

Question 29

Why is phytomenadione less effective in reversing warfarin in those with severe liver disease?

Answer 29

as clotting factors are synthesised in the liver

Question 30

How is hydroxocobalamin administered?

Answer 30

IM injection

Question 31

2 main indications for folinic acid?

Answer 31

• Used to decrease the toxic effects of methotrexate and pyrimethamine
• Can be used to treat folate deficiency that results in anaemia