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anaemia_irondef

iron deficiency anaemia

introduction

  • always attempt to determine the cause of iron deficiency to ensure underlying malignancy or PU disease is excluded.
  • recommended daily iron intake depends upon age and gender:
    • pregnant women = 27mg/d
    • premenopausal women = 18mg/d
  • correcting iron deficiency anaemia takes 2-4 months of oral Rx assuming the underlying cause is managed, but replenishing stores takes another 3-6 months of oral Rx after Hb has returned to normal
  • confirm response to oral iron Rx by checking Hb in 3-4 weeks, it should have risen by 20g/L
  • parenteral iron can usually be avoided, but if needed, it should be given iv as im doses are painful, stain the skin and are poorly absorbed.

common causes of iron deficiency anaemia

increased iron demand

  • rapid growth (eg. infant, adolescent)
  • pregnancy
  • erythropoietin therapy

blood loss

decreased iron intake or malabsorption

  • inadequate diet (eg. vegan)
  • malabsorption
    • hypochlorhydria (eg. long term ppi Rx
    • disease - (eg. coeliac disease)
    • surgery - (eg. post-gastrectomy)
    • inflammation

iron replacement Rx

usual oral dose of elemental iron

  • adults: 100-210mg daily in divided doses
  • children: 2-3mg/kg up to 7mg/kg (max. 210mg) daily in divided doses

some iron preparations

  • Ferro Liquid 30mg/ml ferrous sulfate = 6mg/ml elemental iron
  • FGF - CR tablet 300mcg folic acid plus 250mg dried ferrous sulfate = 80mg elemental iron
  • Fefol - capsule 300mcg folic acid plus 270mg dried ferrous sulfate = 87.4mg elemental iron
  • Ferrograd C - CR tablet 500mg vitamin C plus 325mg dried ferrous sulfate = 105mg elemental iron

drug interactions with oral iron

  • iron absorption is reduced by antacids and calcium - separate dosage times by some hours
  • iron reduces the absorption of bisphosphonates, levodopa, carbidopa, methyldopa and thyroid hormones
  • iron absorption is reduced by and reduces the absorption of oral quinolones and tetracyclines

adverse effects of oral iron Rx

  • it is tolerated better if started at a low dose
  • abdominal pain
  • nausea / vomiting
  • constipation and diarrhoea
  • black stools
  • oral liquid may discolor teeth but this can be prevented by diluting with water and drinking through a straw
  • accidental or intentional ingestion may be fatal - see iron poisoning

some iron rich foods

  • lamb kidney 11mg/100g
  • lean beef 3mg/100g
  • chicken or fish 1mg/100g
  • spinach 4mg/100g
  • wholemeal bread or hard boiled eggs 2mg/100g

intravenous iron infusions

anaemia_irondef.txt · Last modified: 2018/05/26 10:00 (external edit)