1. College of Medicine & Health Sciences Blood Pharmacology 1 Pharmacology of Blood Natnael G.(B.Pharm) May, 2018

2. What makes up our blood? RED BLOOD CELLS (Erythrocytes) – The most abundant cells in our blood; they are produced in the bone marrow and contain a protein called hemoglobin that carries oxygen to our cells. WHITE BLOOD CELLS (Leukocytes) – They are part of the immune system and destroy infectious agents called pathogens. PLASMA – This is the yellowish liquid portion of blood that contains electrolytes, nutrients and vitamins, hormones, clotting factors, and proteins such as antibodies to fight infection. PLATELETS (Thrombocytes) – The clotting factors that are carried in the plasma; they clot together in a process called coagulation to seal a wound and prevent a loss of blood. Blood Pharmacology 2

3. Blood Facts Blood Pharmacology 3  Average adult: FIVE liters--  makes up 7-8% of their body weight.  Blood is living tissue that carries oxygen and nutrients to all parts of the body, and carries carbon dioxide and other waste products back to the lungs, kidneys and liver for disposal. It also fights against infection and helps heal wounds, so we can stay healthy.  There are about one billion red blood cells in two to three drops of blood. For every 600 red blood cells, there are about 40 platelets and one white cell.

4. Genetics of Blood Types Our blood type is established before we are BORN, by specific GENES inherited from our parents. We inherit one gene from our MOTHER and one from our FATHER. These genes determine our blood type by causing proteins called AGGLUTINOGENS to exist on the surface of all of our red blood cells. Blood Pharmacology 4

5. What are blood types? Blood Pharmacology 5 There are 3 alleles or genes for blood type: A, B, & O. Since we have 2 genes, there are 6 possible combinations. Blood Types AA or AO = Type A BB or BO = Type B OO = Type O AB = Type AB

6. Blood Transfusions A blood transfusion is a procedure in which blood is given to a patient through an intravenous (IV) line in one of the blood vessels. Blood transfusions are done to replace blood lost during surgery or a serious injury. A transfusion also may be done if a person’s body can't make blood properly because of an illness. Who can give you blood? People with TYPE O ---  Universal Donors, People with TYPE AB  Universal Recipients, Rh +  Can receive + or - Rh -  Can only receive – Universal Donor Universal Recipient Blood Pharmacology 6

7. Rh Factors Scientists sometimes study Rhesus monkeys to learn more about the human anatomy because there are certain similarities between the two species. While studying Rhesus monkeys, a certain blood protein was discovered. This protein is also present in the blood of some people. Other people, however, do not have the protein. The presence of the protein, or lack of it, is referred to as the Rh (for Rhesus) factor. If your blood does contain the protein, your blood is said to be Rh positive (Rh+). If your blood does not contain the protein, your blood is said to be Rh negative (Rh-). Blood Pharmacology 7 A+ A- B+ B- AB+ AB- O+ O-

8. Agents Affecting Blood & Hematopoietic Organ Blood Pharmacology 8

9.  Thrombosis – the formation of an unwanted clot within the blood vessels or heart. Thrombus: a clot that adheres to a vessel wall. Embolus: intravascular clot that floats in the blood.  Atrial thrombosis: usually consists of a platelet- rich clot.  Venous thrombosis: is triggered by blood stasis or inappropriate activation of the coagulation cascade (a defect in the normal hemostatic defense mechanisms)  involves a clot that is rich in fibrin, with fewer platelets than are observed with arterial clots Blood Pharmacology 9 Dysfunctions of blood

10.  Bleeding disorders –due to failure of hemostasis and include hemophilia and vitamin K deficiency.  Anemia -- caused by nutritional deficiency & others (hereditary,….). Drugs affecting Blood  Antithrombotics Platelet aggregation inhibitors: Aspirin, Ticlopidine & clopidogrel, Abciximab, Eptifibatide and tirofiban. Anticoagulants: UFH,& LMWHs, Argatroban, Lepriudin, Warfarin. Thrombolytic agents: Alteplase, Striptokinase Blood Pharmacology 10

11.  Treatment of Bleeding:  Aminocaproic acid  Aprotinin  Protamine sulphate  Tranexamic acid  Vitamin K  Treatment of anemia:  Vitamin B12  Erythropoietin  Folic acid  Iron  Hydroxyurea (sickle cell anemia) Blood Pharmacology 11

12. Clot formation requires platelet activation and aggregation (white clot or platelet clot), followed by formation of a fibrin clot (red clot). Blood Pharmacology 12

13. ⅫⅫaⅫa ⅪaⅪa ⅨaⅨa ⅩaⅩa Ⅲ a, Ⅶ a Ⅺ Ⅸ Ⅹ Ⅲ, Ⅶ Ⅹ + + ++ + Prothrombin( Ⅱ ) Thrombin( Ⅱ a) Fibrin ( Insoluble) Fibrin (soluble) fibrinogen ++ Ⅹ III Ⅹ IIIa + Fibrin clot Process of normal blood coagulation Extrinsic pathway Extrinsic pathway Intrinsic pathway Intrinsic pathway Blood Pharmacology 13

14. 1. Anticoagulants Anticoagulants are drugs employed in preventing blood coagulation. They inhibit certain clotting factors in the liver. The function of them is to: 1.prevent the formation of new blood clots. 2.keep existing blood clots from growing larger. Blood Pharmacology 14

15. Classification of anticoagulants 1.Anticoagulants both in vivo & vitro: e.g. Heparin 2.Anticoagulants in vivo: dicoumarol 3.Anticoagulants in vitro: Sodium citrate Blood Pharmacology 15

16. 1. Heparin  Source and chemistry Blood Pharmacology 16 1.Large amount of negative charge 2.Strong acidity

17. 1.2 Pharmacological effects Anticoagulative effect MOA : accelerate inactivation of clotting factors.( Ⅱ a, Ⅸ a, Ⅹ a, Ⅺ a, Ⅻ a ) by enhancing the anticoagulative activity of AT Ⅲ (antithrombin Ⅲ ). Blood Pharmacology 17

18. ⅫⅫaⅫa ⅪaⅪa ⅨaⅨa ⅩaⅩa ⅦaⅦa Ⅺ Ⅸ Ⅹ Ⅶ Ⅹ + + ++ + Prothrombin( Ⅱ ) Thrombin( Ⅱ a) Fibrin insoluble Fibrin soluble fibrinogen ++ Ⅹ III Ⅹ IIIa + Fibrin clot Blood Pharmacology 18

19. AT Ⅲ : a plasma protease inhibitor Blood Pharmacology 19

20. Mechanism of heparin This reaction happens in normal physiological state, but it’s very slow and weak. In the presence of heparin (which acts as an catalyst), it will be accelerated by more than 1,000 times Blood Pharmacology 20

21. Characteristics of anticoagulative effect Blood Pharmacology 21 Effective both in vivo and in vitro Quick onset and potent effects Efficacy positively relative to molecular weight

22. 1.2 Pharmacological effects 2. Other effects  Adjusting blood lipid  Anti-inflammatory effect  Anti-proliferative effect on vascular smooth muscle cell  Inhibiting platelet aggregation Blood Pharmacology 22

23. 1.3 Clinical uses 1.Thromboembolic disease: deep venous thrombosis(DVT), pulmonary embolism (PE), unstable angina, acute myocardial infarction, cerebral infarction. 2.Prophylaxis of postoperative venous thrombosis in patients undergoing surgery (for example, hip replacement) and those with acute MI. 3.DIC (Disseminated intravascular coagulation): early stage. 4.Extracorporal circulation: e.g. dialysis machine. 5.For treating pregnant women (do not cross the placenta; due to their large size and negative charge) used when clearly indicated. Blood Pharmacology 23

24. 1.4 Adverse reactions Hypersensitivity (porcine source; antigenic) Spontaneous hemorrhage:  Monitoring of aPTT  Antagonist: Protamine sulfate(1mg:100u) Heparin-induced thrombocytopenia (HIT): (a decrease in circulating platelets), In cases of HIT, heparin can be replaced by another anticoagulant, such as argatroban. LMWHs can have cross-sensitivity and are not recommended in HIT. Osteoporosis (on long-term heparin therapy). Blood Pharmacology 24

25. 1.5 Contraindications: 1. Bleeding disorders/tendency: Severe hypertension, intracranial haemorrhage Ulcer, haemophilia Recent surgery of the brain, eye, spinal cord 2. Hypersensitivity to heparin 3. Alcoholism 4. Infective endocarditis 5. Active tuberculosis 6. Threatened abortion 7. Visceral carcinoma 8. Advanced hepatic or renal disease Blood Pharmacology 25

26. LMWHs (Low Molecular Weight Heparins) Weaker effect than heparin (lower incidence of thrombocytopenia) Low incidence of hemorrhage 1/2 Long-lasting effect (longer t 1/2 ) Small individual deviation (more predictable anticoagulation dose response) Improved SC bioavailability Dose-independent clearance Less need for routine laboratory monitoring Blood Pharmacology 26

27. Coumarin derivatives (oral anticoagulants) Often referred to as oral anticoagulants because they are administered orally, which exists as the main difference from heparin. Blood Pharmacology 27  Warfarin: the only therapeutically relevant coumarin anticoagulant.

28. Pharmacokinetics Absorption: rapid and complete (warfarin) Distribution: PPBR>90% Elimination: liver Excretion: kidney Blood Pharmacology 28

29. 4.1 Pharmacological effects Anticoagulative effect 1.Mechanism: By inhibiting Vitamin K epoxide reductase, which is responsible for the conversion of reduced vitamin K cofactor to vitamin K epoxide (regeneration of Vitamin K). #No regeneration of Vit K → inhibiting the synthesis of clotting factor Ⅱ, Ⅶ, Ⅸ, Ⅹ → inhibiting coagulation. Blood Pharmacology 29 Ⅱ, Ⅶ, Ⅸ, Ⅹ #Several clotting factors ( Ⅱ, Ⅶ, Ⅸ, Ⅹ ) depend on Vit-K as a coenzyme in their complete synthesis by the liver.

30. 2. Characteristics 1.Oral administration 2.Effective in vivo, not in vitro 3.Slow onset, long duration 1 4.Overcome by administration of Vitamin-K 1 Blood Pharmacology 30

31. 4.2 Clinical uses: For long use prevent: Acute DVT or PE Venous throboembolism in patients undergoing orthopedic or gynecological surgery. Systemic embolization in patients with MI, prosthetic heart valves or chronic atrial fibrillation. Blood Pharmacology 31

32. 4.3 Adverse effects Spontaneous hemorrhage:  Monitoring of PT (INR) Tx: – withdrawal of the drug; – administration of Vit-K & fresh blood Others – birth defect (warfarin) – Allergic reaction Blood Pharmacology 32

33. 4.4 Drug interactions Enzyme inducer: barbiturates Competitive antagonist: Vit-K High PPB: aspirin, quinidine, sulfonamide, phenylbutazone Enzyme inhibitor: cimetidine, isoniazid PLT inhibitors: aspirin Blood Pharmacology 33

34. Ⅲ. Anticoagulants in vitro Sodium citrate Potassium oxalate Mechanism: Ca2+ Uses: Prevent blood coagulation in vitro Blood Pharmacology 34

35. 2. Fibrinolytic drugs (thrombolytic agents) Blood Pharmacology 35 These agents can activate the conversion of plasminogen to plasmin, a serine protease that hydrolyzes fibrin and thus dissolves clots. Mainly used in acute thrombosis.

36. Plasminogen inhibitors － + activators Plasmin ＋ + Degradation fibrin splits products fibrinogen fibrin products Blood Pharmacology 36 ( Fibrinolytic drugs)

37. 1.Plasminogen activator from human body: Urokinase (UK), Alteplase (t-PA) 2.Plasminogen activator form bacteria: Streptokinase (SK), Anistreplase, Stephylokinase 3.Plasminogen activator from snake: Snake venom antithrombus enzyme, Ancrod, Acutase Blood Pharmacology 37

38. Shared characteristics Action: All act either direct or indirect to convert plasminogen to plasmin, which in turn cleaves fibrin, thus lysing thrombi. Clot dissolution occurs with a higher frequency when therapy is initiated early after clot formation. Blood Pharmacology 38

39. 1. Streptokinase(SK) Mechanism: acts indirectly SK-plasminogen complex → activate plasminogen Clinical uses: Thrombolytic therapy: early,< 6h  IV route: DVT, multiple pulmonary emboli  Intra-arterial route: myocardial infarction Adverse reactions: Bleeding Hypotension Allergic reaction Blood Pharmacology 39

40. 2. Urokinase(UK) Mechanism: activating plasminogen directly Clinical uses: Same use as SK, especially cerebral embolism Adverse reactions: bleeding, but no antigenicity Blood Pharmacology 40

41. 3. Tissue plasminogen activator (t-PA) Mechanism: act directly Characteristics: act selectively, risk of bleeding ↓ (High affinity to plasminogen bound to fibrin in the embolism, low affinity to free plasminogen). superior to SK and UK Blood Pharmacology 41

42. 3. Antiplatelet drugs Blood Pharmacology 42 Drug that inhibits platelets from aggregating to form a plug. They are used to prevent clotting and alter the natural course of atherosclerosis.

43. Blood Pharmacology 43 Platelets activation processes involve three steps: 1.Adhesion to the site of injury 2.Release of intracellular granules 3.Aggregation of the platelets.

44. Classification 1.Inhibitors of platelet metabolism 2.Agents inhibiting platelet activity induced by ADP: Ticlopidine 3.Thrombin inhibitor: argatroban 4.GP Πb / Шa receptor blocker: abciximab Blood Pharmacology 44

45. AA TXA 2 ( － ) ( ＋ ) AC AC PDE cAMP ↓ cAMP↑ 5-AMP ↑aggregation ↓aggregation (PLT) (endothelium) Blood Pharmacology 45 aspirin s - Dipyridamole - + aspirin l COX - PGI 2

46. 1.Inhibitors of platelet metabolism A.Cyclooxygenase inhibitors: Aspirin B.PDE inhibitors : Dipyridamole C.TXA2 synthetase inhibitor: Ridogrel D.Activators of adenylate cyclase: epoprostenol (PGI2) Blood Pharmacology 46

47. A. Cyclooxygenase inhibitors: Aspirin Aspirin is a classic old drug which is used as a NSAIDs for more than 100 years. Besides antipyretic, analgesic and anti-inflammatory activities, it can inhibit platelet aggregation. Blood Pharmacology 47 Pay attention!  at small dose (50 ～ 75mg/d) ： inhibit the synthesis of TXA2 – which causes platelet aggregation.  at higher doses (> 320 mg/day) ： inhibits the synthesis of PGI2 – which inhibits platelet aggregation.

48. Clinical Uses Prophylaxis after cardiac operation to reduce the incidence of recurrent myocardial infarction (MI). Prophylaxis for transient ischemic attacks (TIA) or post TIA. Blood Pharmacology 48 B. TXA2 synthetase inhibitor: Ridogrel More effective than aspirin Fewer adverse reaction

49. C. PDE inhibitors: Dipyridamole Mechanism: 1. ↓ PDE → cAMP ↑ ↓ aggregation 2. ↓ the uptake of adenosine →↑ AC Clinical use: Substitute of aspirin – prosthetic heart valves, etc. Blood Pharmacology 49

50. Agents inhibiting platelet activity induced by ADP: Ticlopidine Broad spectrum inhibitor of PLT aggregation Mechanism: disturb the release of α-granule and binding of fibrin to GP Ⅱ b/ Ⅲ a receptor induced by ADP Clinic use: thromboembolic disease Severe toxicity: nausea, bone marrow depression Blood Pharmacology 50

51. Thrombin inhibitor: Argatroban Thrombin inhibitor Has a short half-life, is given by continuous intravenous infusion, and monitoring is done by aPTT. Its clearance is not affected by renal disease but is dependent on liver function. Blood Pharmacology 51

52. GPΠb / Шa receptor blocker: abciximab activation of glycoprotein receptor on PLT membrane is the final common pathway for platelet aggregation. MOA: blockade of glycoprotein receptors on PLT membrane. Blood Pharmacology 52

53. 4. Hemostatics Blood Pharmacology 53 1. Coagulants: Vitamin K 2. Antifibrinolytic drugs: Tranexamic acid, Aminomethylbenzoic acid 3. Thrombin 4. Vasoconstrictors: Etamsylate Posterior pituitary

54. 1.Vitamin K Source and types Vitamin K is found in meats, dairy products, leafy green vegetables. Two natural forms : VitK1,VitK2 Two synthesized forms: VitK3,VitK4 Blood Pharmacology 54

55. Mechanism of vitamin K Blood Pharmacology 55 Ⅱ, Ⅶ, Ⅸ, Ⅹ Some clotting factors ( Ⅱ, Ⅶ, Ⅸ, Ⅹ ) that are involved in the coagulation reactions depend on vitamin K as a coenzyme in their complete synthesis by the liver.

56. Clinical uses: Hemorrhage resulting from Vit-K deficiency; 1.Excess of oral anticoagulants, 2.Obstructive jaundice and biliary fistula (Vitamin K is a fat-soluble vitamin) 3.Long term use of broad spectrum antibiotics: (some vitamin K is synthesized by intestinal bacteria.) 4.Prevent hemorrhage in newborn baby and premature infants. Blood Pharmacology 56

57. 2. Anti-fibrinolysin Aminomethylbenzoic acid Mechanism: 1.inhibit plasminogen activation 2.inhibit the activity of plasmin (large dose) Clinical uses: bleeding due to high activity of plasmin Adverse reactions: intravascular thrombosis Blood Pharmacology 57

58. Plasminogen inhibitors － + activators ( Anti-fibrinolysin ) Plasmin ＋ + Degradation fibrin splits products fibrinogen fibrin Products Blood Pharmacology 58

59. 3. Thrombin (Factor Ⅱ )  Extracted from animal blood  Activate fibrinogen to fibrin  Used to stop bleeding or hemorrhage. Blood Pharmacology 59

60. 5.Agents Used in Anemia Haematopoiesis: it is the production of erythrocytes, platelets, and leukocytes from undifferentiated stem cells. It requires a constant supply of essential nutrients – iron, vit B12, folic acid and presence of hematopoietic growth factors. Blood Pharmacology 60 Introduction

61. Anemia: a common clinical condition that is caused by an acquired or hereditary abnormality of RBCs or its precursor, or it may be a manifestation of an underlying non hematologic disorder. Anemia is defined as a decrease in the circulating RBC mass; the usual criteria are a Hb of less than 12gm/dl (12-16gm/dl) in women and less than 14gm/dl (14-18gm/dl) in men. Blood Pharmacology 61

62. Signs and Symptoms:  Hypoxia( fatigue, headache, dyspnea, angina, tachycardia, visual impairment, hepatic and or splenic enlargement, bone tenderness, blood loss in feces. Blood Pharmacology 62

63. Classification of anemia:  Anemia associated with decrease RBC production : A.Iron deficiency anemia ( microcytic anemia ) B.Folic acid deficiency anemia (megalobl.anemia) C.Vit B 12 def (macrocytic, pernicious) D.Thalassemia and sickle cell anemia (a blood disorder passed down through families (inherited)-Rx blood transfusion. E.Anemia due to chronic disease and renal failure.  Anemia due to increased RBC destruction:  Hemolytic anemia (due to hemolysis) Blood Pharmacology 63

64. Anti anemic Drugs Iron preparation: 1. Oral iron, 2. Parenteral iron 1. oral iron A) Ferrous sulfate - 325mg - 65mg elementaliron B )Ferrous gluconate - 320mg -37mg elem.iron C) Ferrous fumarate - 325mg - 106mg elem.iron 2. Parenteral iron: iron dextran 50mg elem.iron/ml Clinical use of iron: Iron deficiency anaemia is the only indication for the use of iron Blood Pharmacology 64

65. 200- 400mg oral elemental iron daily should be given to correct anaemia (25% absorbed,so 50- 100mg iron can be incorporated in Hb). Treatment should be continue for 3-6 months, this not only correct the anaemia but will replenish iron stores. (Hb should reach normal level in 1-3 months). Failure to respond to oral iron therapy may be due to incorrect diagnosis. Blood Pharmacology 65

66. Adverse effects: Due to oral iron therapy;  Nausea, epigastric discomfort, abdominal cramps, constipation, diarrhea, black stool. Blood Pharmacology 66

67. Parenteral iron therapy: 1. It should be reserved for patients with documented iron deficiency unable to tolerate or absorb iron 2. Pts. With extensive chronic blood loss who can not be maintained with oral iron alone. Blood Pharmacology 67

68. Adverse effects:  Local pain, tissue staining( brown discoloration of tissues overlying the inj. site), headache, fever, vomiting, bronchospasm, anaphylaxis, and death Blood Pharmacology 68

69. VITAMIN B 12  Vitamin B 12 (cobalamine), a cobalt containing molecule is along with folic acid, a cofactor in the transfer of 1- carbon units, a step necessary for the synthesis of DNA; either vitaminB12 or folic acid deficiency usually manifests first as anaemia (megaloblastic anaemia) OR (pernicious) anemia (associated with Vit B12 only) Blood Pharmacology 69

70.  Administration of folic acid to pts. With Vit B12 deficiency helps partially or fully corrects anaemia.  However exogenous folic acid does not correct the neurologic defects (peripheral neuropathy) of Vit B12 deficiency.  Because Vit B12 def. anaemia is almost always caused by inadequate absorption, therapy should be by replacement of VitB12,using parenteral therapy.  No significant toxicity of VitB12 occurred. Blood Pharmacology 70

71. Folic acid: Like Vit B12 folic acid is required for normal DNA synthesis, and its def. usually presents as megaloblastic anaemia. In addition deficiency of folic acid during pregnancy increase the risk of neural tube defects in the fetus; folic acid supplementation is recommended prior to and during pregnancy Blood Pharmacology 71

72. Erythropoietin: (hormone control Erythropoiesis)  produced by the kidney  Reduction in its synthesis is responsible for anemia of renal failure  Activation of receptors on erythroid progenitors in the bone marrow, it stimulates the production of red cells and increases their release from B. M Blood Pharmacology 72

73. Erythropoietin is used for anemia associated with renal failure and some time effective for patients with other forms of anemia. Example:  Primary bone marrow disorder or anemia secondary to cancer chemotherapy or  HIV treatment, bone marrow transplantation, Toxicity: thrombosis, cardiovascular events when used along with some other erythropoietic agents. Blood Pharmacology 73

74. Any question??? Thank you!!! Blood Pharmacology 74