Hematology Quiz: Hematinics and Iron Preparations

Hematinics

• Hematinics are agents used for blood formation and treating anemia. Iron, vitamin B12, and folic acid are main hematinics.

Iron Preparations

Oral Iron Preparations

• Taken after meals to avoid GI irritation.
• Treatment duration: 3-6 months.
• Ferric Ammonium Citrate: Lowest oral absorption.
• Ferrous Sulfate: Most irritating.
• Ferrous Fumarate & Ferrous Gluconate: Less irritating, suitable for children.
• Iron Choline Citrate: (Tablet or solution), less irritating iron salt.
• Carbonyl Iron Microparticles: Purified iron, slower absorption with continued iron release (1-2 days).

Parenteral Iron Preparations

• Indications:
  • Patients unable to absorb oral iron (malabsorption syndromes, GI inflammatory conditions).
  • Patients who cannot tolerate oral iron preparations.
  • Patients with chronic renal failure or chemotherapy-induced anemia receiving erythropoietin treatment.
• Iron-sucrose IV
• Iron-Sorbitol-Citric Acid complex IM
• Iron Dextrin IV
• Iron Dextran IM & IV

Uses of Hematinics

• Treatment of iron deficiency anemia.
• Compensation for iron depletion during megaloblastic anemia.

Adverse Effects

• Oral iron: Nausea, abdominal cramps, diarrhea, dark stools.
• Parenteral iron: Hypersensitivity and anaphylactoid reactions. Excessive iron may worsen infections; avoid during infection.
• Acute iron toxicity (children): Severe necrotizing gastritis, vomiting, hemorrhage, diarrhea, and circulatory collapse.
• Chronic iron toxicity (iron overload): Occurs in chronic hemolytic anemias needing frequent blood transfusions (like thalassemias).

Treatment of Iron Toxicity

• Iron chelators: Desferrioxamine (slow SC infusion in chronic toxicity, IM or IV in acute toxicity).
• Deferiprone: Orally absorbed iron chelator, alternative for thalassemic patients who cannot take desferrioxamine.
• Deferasirox: Similar to deferiprone, can cause gastrointestinal bleeding.
• Symptomatic treatment: Correcting acid-base and electrolyte disturbances.

Cyanocobalamine (Vitamin B12)

Uses and Preparations

• Cyanocobalamine: Treatment and prophylaxis of pernicious anemia (especially after gastrectomy), correcting neurological abnormalities in diabetics.
• Hydroxocobalamin: Preferred in pernicious anemia due to rapid response and high protein binding.
• Methylcobalamin: Correcting neurological abnormalities in diabetics (doesn't need intrinsic factor for absorption).
• Lipotropic: In hepatotoxicity from general anesthetics.

Adverse Effects

• Iron deficiency anemia due to rapid increase in erythropoiesis and depletion of iron stores (iron supplementation needed during B12 therapy).
• Hypokalemia and hyperuricemia.
• Allergic reactions.

Folic Acid

Uses

• Treatment or prevention of anemia (associated with pernicious anemia and megaloblastic anemia, liver disease, hemolytic anemia, and those taking anticonvulsants).
• Treatment of pernicious anemia (in combination with B12).
• Megaloblastic anemia treatment.

Adverse Effects

• Oral folic acid is generally nontoxic in large doses.
• Injections rarely cause sensitivity reactions

Hematopoietic Growth Factors

Erythropoietin (EPO)

• Glycoprotein produced in kidneys and macrophages.
• Responsiveness to blood loss or low tissue oxygen tension.
• Recombinant human erythropoietins (Epoetin-alfa) - produced in cultured mammalian cells.
• Extended-release version (darbepoetin).
• Parenteral administration (IV or SC) due to degradation in the gastrointestinal tract.
• Half-life (T½) varies based on normal or chronic renal failure.

Elimination

• Binding to receptors leads to internalization and degradation of the ligand.
• Degradation by reticuloendothelial pathway or lymphatic system.
• Minimal unchanged excretion.

Dynamics

• EPO stimulates stem cells to become proerythroblasts and promotes reticulocyte release from the bone marrow.
• Regulates red blood cell proliferation and differentiation.

Uses

• Chronic renal failure anemia; chemotherapy-induced anemia; anemia in AIDS patients; prevention of anemia in premature infants; increasing yield of autologous blood donations.

Adverse Effects

• Common: Transient influenza-like symptoms.
• Serious: Hypertension, encephalopathy (headache, disorientation, seizures).
• Increased risk of thrombosis, especially during dialysis (due to increased hematocrit and blood viscosity).

Myeloid Growth Factors (Filgrastim & Sargramostim)

• Filgrastim: Recombinant human granulocyte colony-stimulating factor (G-CSF) regulates neutrophil production and function.

• Sargramostim: Recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) regulates granulocyte, basophil, and eosinophil production, and other myeloid cells.

• Uses: Reduce neutropenia following drugs and cytotoxic therapies (such as chemotherapy or bone marrow transplantation).

• Adverse effects: Bone pain, splenomegaly, increased uric acid concentrations (Filgrastim); fluid accumulation in pleural and pericardial cavities (Sargramostim).

Megakaryocyte Growth Factors (Eltrombopag & Romiplostim)

• Eltrombopag: Small molecule agonist (oral).
• Romiplostim: Dimerized fusion protein (SC).
• These are thrombopoietin agonists that bind to and activate thrombopoietin receptors.
• Stimulate the proliferation and maturation of megakaryocytes, and platelet formation.
• Uses: Idiopathic thrombocytopenic purpura, aplastic anemia, and chronic hepatitis C-associated thrombocytopenia.

Drug-Induced Megaloblastic Anemia

• Neomycin
• Colchicine
• Antiepileptic drugs (reduce B12 absorption)

Folic Acid (Pteroylglutamic Acid)

• Nutritional megaloblastic anemia
• Malabsorption syndrome
• Alcoholics and pregnant women
• Liver disease and hemolytic anemia
• Patients with anticonvulsant drugs
• Dialysis patients (removed with each treatment)

Drug-Induced Blood Disorders

Hemolytic Anemia

• Antimalarial drugs
• Aspirin
• Sulfonamides
• Quinine and Quinidine
• Penicillin
• Sulfonamides
• Methyldopa

Thrombocytopenia

• Heparin
• Rifampin
• Indomethacin
• Quinine
• Quinidine

Bone Marrow Depression (Aplastic Anemia/Agranulocytosis)

• Cytotoxic drugs
• Chloramphenicol
• Chlorpromazine
• Thiouracil

Test your knowledge on hematinics, their role in blood formation, and the various types of iron preparations. This quiz covers oral and parenteral iron treatments, including indications and specific formulations. Perfect for students and professionals in the medical and health fields.