Pathophysiology of Anemia


Pharmacology of Anemia

Anemia is a decrease in the number of RBCs, Hematocrit (volume percentage (%) of red blood cells in blood), or Hb content.

Prescription contains:

  •   Iron supplement (oral/parenteral)
  •   Erythropoiesis-stimulating agents (Erythropoietin,Epoetin alfa ,Epoetin beta ,Darbepoetin alfa,Methoxy polyethylene glycol-epoetin beta)

Check for symptoms

  • Most commonly, people with anemia report feelings of weakness, or fatigue, general malaise(uneasiness), and sometimes poor concentration. They may also report dyspnea (shortness of breath) on exertion.
  • In very severe anemia, the body may compensate for the lack of oxygen-carrying capability of the blood by increasing cardiac output. The patient may have symptoms related to this, such as palpitations, angina (if pre-existing heart disease is present), intermittent claudication(muscle pain) of the legs, and symptoms of heart failure.
  • In severe anemia, there may be signs of a hyperdynamic circulation: tachycardia (a fast heart rate), bounding pulse, flow murmurs, and cardiac ventricular hypertrophy (enlargement). There may be signs of heart failure.
  • The consumption of non-food items such as ice, but also paper, wax, or grass, and even hair or dirt, may be a symptom of iron deficiency, although it occurs often in those who have normal levels of hemoglobin.
  • Chronic anemia may result in behavioral disturbances in children as a direct result of impaired neurological development in infants, and reduced scholastic performance in children of school age. Restless legs syndrome is more common in those with iron-deficiency anemia.


Anemia is typically diagnosed on a complete blood count.

Normal Haemoglobin according to W.H.O

Age or gender group

Hb threshold (g/dl)

Hb threshold (mmol/l)

Children (0.5–5.0 yrs)



Children (5–12 yrs)



Teens (12–15 yrs)



Women, non-pregnant (>15yrs)



Women, pregnant



Men (>15yrs)



Classification of Anemia by Cause:

  • Blood loss

  • Deficient erythropoiesis

  • Excessive hemolysis (RBC destruction)

  • impaired red blood cell (RBC) production,
  • increased RBC destruction (hemolytic anemias),
  • blood loss and fluid overload (hypervolemia).
  • Several of these may interplay to cause anemia eventually. Indeed, the most common cause of anemia is blood loss, but this usually does not cause any lasting symptoms unless a relatively impaired RBC production develops, in turn most commonly by iron deficiency.

Counselling on side effects:

  • When taking iron supplements, stomach upset and/or darkening of the feces are commonly experienced. The stomach upset can be relieved by taking the iron with food; however, this decreases the amount of iron absorbed. Vitamin C aids in the body’s ability to absorb iron, so taking oral iron supplements with orange juice is of benefit.


  • Milk products and Calcium supplements decrease the absorption of iron so more time gap to be maintained between iron supplements and calcium supplements.

Toxic dosage

The amount of iron ingested may give a clue to potential toxicity. The therapeutic dose for iron deficiency anemia is 3–6 mg/kg/day. Toxic effects begin to occur at doses above 10–20 mg/kg of elemental iron. Ingestions of more than 50 mg/kg of elemental iron are associated with severe toxicity.

  • A 325-mg tablet of ferrous sulfate has 65 mg (20%) of elemental iron

  • A 325-mg tablet of ferrous gluconate has 39 mg (12%) of elemental iron

  • A 325-mg tablet of ferrous fumarate has 107.25 mg (33%) of elemental iron


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