Pharmacology of Anemia/growth factors Flashcards
If iron deficiency anemia is severe, what do you treat it with?
RBC transfusion
What is iron regulated by?
How can this be bypassed?
1) Hepcidin
2) Iron infusion
Microcytic anemia due to reduced heme synthesis is caused by?
Due to reduced globin production is caused by?
1) Lead poisoning
2) Thalassemic disorders
How much oral iron should be taking in a day?
What should you take it with and why?
1) 200-400 mg divided into 2-3 doses a day
2) With liquids because food inhibits absorption
What are examples of oral iron and ideally what features do you want it to not have so that you can avoid poor absorption?
1) Ferrous sulfate/gluconate/fumarate
2) Not enteric-coated and not sustained-release
Parenteral iron therapy such as iron dextran, sodium ferric gluconate complex and iron-sucrose complex all have?
An iron oxyhydroxide core surrounded by carbohydrate
What is a new nanoparticle-based iron preparation that can be administered quickly (time increased from 15 sec to 5 min) and is tolerated much better than iron dextran?
Ferumoxytol
No matter the form of iron therapy we can expect what results?
Reticulocytosis in a few days and an increase in Hb in 2 wks
Acute iron toxicity is seen almost exclusively in young children who accidentally ingest iron tablets, how many is considered to be lethal?
10 tablets
Urgent treatment for acute iron toxicity includes?
1) Whole bowel irrigation
2) Parenteral deferoxamine
With chronic iron toxicity (hemochromatosis), iron deposits in what organs leading to their failure?
When do we see this?
1) The heart, liver, pancreas
2) With hereditary hemochromatosis and patients who receive many red cell transfusions over a long period of time
How much vitamin B12 do we need a day?
How much does the body store and where is most stored?
1) 2 µg/day
2) 2 – 5 mg which about half is in liver
Why does it take years to develop vitamin B12 deficiency after normal absorption ceases?
Because the normal body stores greatly exceed the daily requirement
What effect does nitrous oxide have on vit B12 when inhaled for analgesia during surgery?
Inactivates cyanocobalamin (common form of vitamin B12)
What happens if vit B12 body stores are depleted?
Rapid onset neurological dysfunction (e.g., paresthesias, weakness, spasticity) that may not fully reverse
What does cobalamin form a complex with so that it can bind to the cubulin receptor in the ileum in order to be absorbed?
Intrinsic factor (IF)
What is the most common cause of vitamin B12 deficiency?
Pernicious anemia
Pernicious anemia can cause what two autoantibody formations that blocks what?
1) IF-Cbl interaction
2) IF-Cbl receptors in ileum
Chronic atrophic gastritis from vitamin B12 deficiency is due to autoantibodies directed against?
H-K-ATPase of the parietal cells
How is vitamin B12 deficiency treated if no neurological symptoms are present?
Oral supplementation of 500X the daily need
How is vitamin B12 deficiency treated if neurological symptoms are present?
Parenteral therapy
Why do you want to give twice the daily allowance of folate for pregnant and lactating women compared to normal adults (400 µg/day compared to 800)?
Prevent spina bifida/cleft palate
Folate is absorbed in the jejunum, enters plasma, rapidly cleared by hepatocytes and other cells where it is trapped by?
Polyglutamation
What are the usual causes of folate deficiency?
Inadequate dietary intake or alcoholism
