Blood: Anaemias Flashcards
What is sickle-cell disease caused by?
Structural abnormality of haemoglobin resulting in deformed, less flexible red blood cells. Acute complications in the more severe forms include sickle-cell crisis, where infarction of the microvasculature and blood supply to organs results in severe pain.
What drug can reduce the frequency of crises and the need for blood transfusions in sickle-cell disease? When do the beneficial effects of treatment with this drug become evident? (both generic drug and brand name begin with ‘H’)
Hydrea, Hydroxycarbamide, beneficial effects may not become evident for several months.
What is G6PD deficieny? Who is it more prevalent in?
Glucose 6-phosphate dehydrogenase deficiency is highly prevalent in people from Africa, most parts of Asia, Oceania and Southern Europe. More common in males than females.
Individuals with G6PD are susceptible to developing what?
Acute haemolytic anaemia when they take are number of common drugs or when they eat fava beans (broad beans): Favism, can be severe in children or when eaten raw.
What three points should be kept in mind when prescribing for patients with G6PD deficieny?
- It is genetically heterogenous: haemolytic risk varies and just because a drug is safe in one individual with the disease does not mean it is safe in another.
- Manufacturers do not routinely test drugs for their effects in G6PD-deficient people.
- The risk and severity of haemolysis is almost always dose-related.
What antibiotics have a definite risk of haemolysis in most G6PD-deficient people?
- Nitrofurantoin
- Quinolones
- Sulfonamides (including co-trimoxazole)
What drug used in the prophylaxis and treatment of acute hyperuricaemia, before and during initiation of chemotherapy, in patients with haematological malignancy and high tumour burden at risk of rapid lysis has a definite risk of haemolysis in patients with G6PD-deficiency?
Rasburicase
What are Epoetins?
Recombinant human erythropoietins.
What are Epoetins (Recombinant human erythytopoietins) used for? (3)
- To treat anaemia associated with erythropoietin deficiency in chronic renal failure.
- To increase the yield of autologous blood in normal individuals.
- To shorten the period of symptomatic anaemia in patients receiving cytotoxic chemotherapy.
What is Epoetin beta used for the prevention of in preterm neonates of low birth-weight and why should only unpreserved formulatins be used?
Prevention of anaemia and only unpreserved formulations should be used because other preparations may contain benzyl alcohol.
What are the benefits of darbepoetin alfa versus epoetin?
It is a hyperglycosylated derivative which has a longer half life and can be administered less frequently.
Methoxy polyethylene glucol-epoetin beta is a continous erythropoietin receptor activator that is licensed for what?
Treatment of symptomatic anaemia associated with chronic kidney disease - longer duration of action than epoetin.
Treatment with an iron preparation is justified only in the presence of demonstrable iron-deficiency state. Before starting treatment, what should be excluded?
Gastric erosion
Gastro-intestinal cancer
The oral dose of elemental iron for iron-deficiency anaemia should be what?
100-200mg elemental iron daily.
Some oral preparations of iron contain ascorbic acid for what reason
To aid absorption but the therapeutic advantage of such preparations is minimal and cost may be increased