Mech of action:
•Inhibits the synthesis of Vit K
•Delayed onset of action (8-12hrs) due to presence of
preformed clotting factors in the circulation.
•Therapeutic effect is monitored by Prothrombin time &
International Normalized Ratio.
Prothrombin Time ( risk of bleeding)
• Hepatic microsomal inhibitors (↓ Metabolism ↑toxicity)
Cimetidine, Metronidazole, Ciprofloxacin, Ketoconazole
• Displacement from plasma protein ( Sulfonamides ↑toxicity)
Prothrombin Time ( therapeutic effects)
• Hepatic microsomal Inducers ( ↑ Metabolism & ↓ efficacy)
Phenytoin, Carbamazepine, Rifampicin
• Cholestyramine (↓ Absorption of Warfarin)
• Binds Antithrombin III & potentiates its action 1000 times
(Antithrombin III inhibits thrombin (IIa),VIIa, IXa, & Xa)
• Rapid onset of action because it acts on preformed clotting
• Therapeutic effect is monitored by Activated Partial
PK; Given by SC/IV ( IM = Hematomas, to be avoided)
• No transplacental passage - safe during pregnancy
Low Molecular Weight HEPARINS; Enoxaparin, Dalteparin
• ↑ Bioavailability from SC inj,
• Long duration of action
• Less thrombocytopenia
Contraindications of Heparin:
• Hypersensitivity to the drug,
• Bleeding disorder,
• Severe hypertension,
• Intracranial hemorrhage,
• Ulcerative lesions of GIT,
Direct Thrombin Inhibitors
HIRUDIN obtained from medicinal leeches (Hirudo medicinalis)
• Inhibits Thrombin (IIa)
• Administered by IV,
• Therapeutic effects monitored by aPTT
USES: In patients with thrombosis related to Heparin induced
Adverse effects: Bleeding & Hypersensitivity
• Inhibit ADP mediated platelet aggregation
• Synergistic action with Aspirin
Similar to Aspirin & in patients who can not tolerate Aspirin
Adv effects (Ticlopidine):
• Severe neutropenia,
• Thrombotic thrombocytopenic purpura.
• Substances required in the formation of blood cells& their
deficiency results in anemia.
• Vit B12, Folic acid & Iron (Maturation factors for blood cells)
• Essential for the synthesis of DNA.
• Deficiency causes Megaloblastic anemia
– Immature red cells in the blood & bone marrow.
Parenteral : Cyanocobalamine & Hydroxycobalamin
Oral : Methylcobalmin
•Prophylaxis & treatment of Megaloblastic anemia (B12 def.)
– Given by i.m lifelong.
•Prophylaxis during pregnancy & lactation ( ↑ demand)
•Dietary deficiency, ↑ demand (children, pregnancy & lactation).
• Drug induced. Methotrexate, Cotrimoxazole & Trimethoprim.
Manifestations - Megaloblastic anemia, glossitis, diarrhea & weakness
•Treatment of Megaloblastic anemia
– given along with vit. B12.
•Prophylaxis during pregnancy, lactation, infancy
•Prevention of Methotrexate induced toxicity
– (Folinic acid or Leucovorin rescue)
Preparations of iron:
-Ferrous sulfate Iron dextran i.m/i.v
-Ferrous fumerate Iron sorbitol-citric-acid i.m
-Ferrous gluconate Sodium ferric gluconate i.v.
Oral route: Epigastric pain, vomiting, metallic taste, constipation
(due to astringent effect) staining of teeth & black colored stool
Parenteral route: pain & discoloration of skin at the injection site,
Arthralgia, lymphadenopathy, Urticarial rash & Anaphylaxis
Indications for parenteral iron therapy:
•Intolerance to oral iron.
•Failure to absorb oral iron- severe malabsorption,etc
•Non-compliance to oral iron
•Severe anemia (pregnancy).
•Severe deficiency with bleeding.
•Along with erythropoietin in patients with renal disease.
Antidote : Desferroxamine ( Fe chelating agent)
• Its secretion ↓in patients with renal failure.
• Preparation : Recombinant human erythropoietin I.V/S.C.
• Anemia of chronic renal failure
• Anemia in AIDS patients treated with Zidovudine
• Anemia of Cancer chemotherapy
• Flu like syndrome, Hypertension