CLINICAL PHARMACOLOGY 2003 (PART 30)

Rational use of haematinic drugs is essential to the correction of anaemia in its various forms. The emergence of haemopoietic growth factors as drugs that stimulate erythroid or myeloid cell lines has opened the way to successful management of other forms of haematological disease. Iron: therapy, acute overdose Vitamin B12 (cobalamins) Folic acid Haemopoietic growth factors Sickle cell anaemia Polycythaemia rubra vera Aplastic anaemiacolouring matter of the blood and the defective nature of the colouring matter in anaemia were recognised. In fact iron is essential not only to oxygen transport by red cells but as a catalyst for...
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CLINICAL PHARMACOLOGY 2003 (PART 30) 29 Cellular disorders and anaemias colouring matter of the blood and the defective SYNOPSIS nature of the colouring matter in anaemia were recognised. In fact iron is essential not only to Rational use of haematinic drugs is essential to oxygen transport by red cells but as a catalyst for the correction of anaemia in its various forms. oxidative metabolism in all cells. The emergence of haemopoietic growth factors as drugs that stimulate erythroid or myeloid cell lines has opened the way to successful management of other forms of • Total body iron is 3-5 g (40-50 mg/kg) (male > female). haematological disease. • Haemoglobin contains about two-thirds of total body iron. Iron: therapy, acute overdose • Stores comprise about one-third (ferritin, a water- Vitamin B12 (cobalamins) soluble protein-iron complex, and haemosiderin, an Folic acid insoluble aggregate) in liver, marrow, spleen and Haemopoietic growth factors muscle. Sickle cell anaemia • 5-10% is present in tissues throughout the body in Polycythaemia rubra vera myoglobin, a variety of heme enzymes (e.g. Aplastic anaemia cytochromes) and non-haem enzymes (e.g. metalloflavoproteins) • Average Western diet contains 10-15 mg iron/day.Leukaemias and lymphomas: see Chapter 30 • Normal human absorbs 5-10% dietary iron, i.e. 0.5-1.0 mg/d, which is adequate for an adult male or postmenopausal female but the menstruating or pregnant woman requires 1-3 mg/d. Iron • Iron deficient or pregnant woman absorbs about 30% of dietary iron.Iron, which was the metal symbolising strength in • Iron is lost from the body mainly in desquamated skinmagical systems, used to be given to people and gut cells and the daily loss in men is undersuffering from weakness, and no doubt many were I mg/day, in normal menstruating females 1.5 mg/daybenefited, some psychologically (placebo reactors) and in pregnancy averages 2 mg/day.and others because the weakness was due to iron • Menstrual loss is about 30 mg/period; menstruatingdeficiency anaemia. The rational use of iron could women may therefore be in negative iron balance.not begin until both the presence of iron in the 587 29 CELLULAR DISORDERS AND ANAEMIASIRON KINETICS precursors where it is used to form haem. The major pathway of internal iron exchange is aIron absorption takes place predominantly in the unidirectional flow from plasma transferrin to theduodenum where the acid environment enhances erythron (defined as all red cell elements at anysolubility, but also throughout the gut, allowing stage of maturity), to the macrophage and back tosustained-release preparations to be used. Most plasma transferrin. Over 80% of the iron passingiron in food is present as ferric hydroxide, ferric- through the transferrin compartment each day isprotein complexes or haem-protein complexes. flowing to and from the erythron. Immature redFerrous (Fe++) iron is more readily absorbed than ...