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Fibrinolytics & antifibrinolytics

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Fibrinolytics & antifibrinolytics

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Fibrinolytics & antifibrinolytics

  1. 1. FIBRINOLYTICS & ANTIFIBRINOLYTICS By Dr.Elza Emmannual
  2. 2. FIBRINOLYTICS
  3. 3. Drugs used to lyse thrombi to recanalize occluded blood vessels
  4. 4. Works by activating the natural fibrinolytic system
  5. 5. NATURAL FIBRINOLYTIC SYSTEM
  6. 6. PLASMINOGEN FIBRIN FRAGMENTS FIBRIN PLASMIN ACTIVATORS t-PA, Kallikrein,Factor Xa INHIBITORS α2 Antiplasmin α2 Macroglobulin
  7. 7. • Venous thrombi lysed more easily • Recent thrombi respond better • Little effect on thrombi >3 days old
  8. 8. Clinically important fibrinolytics are, • Streptokinase • Urokinase • Alteplase (rt PA) • Reteplase • Tenecteplase
  9. 9. Streptokinase • Source:β haemolytic streptococci group C • Inactive as such • Combines with circulating plasminogen  forms activator complex  proteolysis of plasminogen  Active plasmin • Cheap,widely used in India
  10. 10. Disadvantages 1.Activates both circulating & fibrin bound plasminogen Depletion of circulating plasminogen → bleeding 2. Antistreptococcal Abs from past infections inactivate considerable fraction of initial dose , loading dose needed 3.AntigenicHSR & anaphylaxis when used for 2nd time 4.Repeat doses less effective due to neutralisation by Abs
  11. 11. Urokinase • Isolated from human urine ,now from cultured human kidney cells • Activates plasminogen directly • Moderately specific to fibrin bound plasminogen • Nonantigenic • Indicated in whom streptokinase has been used for an earlier episode
  12. 12. Alteplase Produced by recombinant DNA technology •Nonantigenic •Short t1/2 so given as slow IV infusion •Expensive Reteplase Produced by recombinant DNA technology •Modified form of rt-PA •Long acting •So given as bolus dose repeated in 30 min
  13. 13. Tenect eplase Produced by r DNA technology •Mutant variant of rt-PA •Long duration of action •Single IV bolus
  14. 14. USES 1.Acute MI – – chief indication,alternate to emergency percutaneous coronary intervention with stent placement – Golden period-1hr,Better results- within 3hrs – Timelag in starting infusion is critical in • Reducing area of necrosis • Preserving ventricular function • Reducing mortality
  15. 15. 2.Deep vein thrombosis 3.Pulmonary embolism 4.Peripheral arterial occlusion 5.Stroke- – rt-PA –approved for treatment of ischaemic stroke – treated within 3 hours of onset – intracranial hemorrhage has to be ruled out
  16. 16. CONTRAINDICATIONS • All situations where the risk of bleeding is increased – Recent trauma – Surgery – Biopsy – Hemorrhagic stroke – Peptic ulcer – Severe hypertension – Aneurysms – Bleeding disorders – Diabetes – Acute pancreatitis – pregnancy
  17. 17. ANTIFIBRINOLYTICS
  18. 18. Drugs which inhibit plasminogen activation & dissolution of clot
  19. 19. EPSILON AMINO-CAPROIC ACID(EACA) • Analogue of lysine • Binds to lysine binding sites of plasminogen & plasmin so that it cannot bind to fibrin & lyse the clot
  20. 20. USES • Overdose of fibrinolytics • To prevent recurrence of G.I & subarachnoid hemorrhage • Certain traumatic & surgical bleedings like prostatectomy,tooth extraction in haemophiliacs • Abruptio placentae,PPH & menorrhagia
  21. 21. Adverse Effects • In hematuria –ureteric obstruction by the unlysed clots • Intravascular thrombosis • Hypotension,bradycardia,arrhythmias • Caution in impaired renal function • Myopathy
  22. 22. TRANEXAMIC ACID • MOA-similar to EACA • 7 times potent than EACA • Preferred drug for bleeding due to – Fibrinolytic drugs – Cardiopulmonary bypass surgery – Tonsillectomy,prostatic surgery,tooth extraction in haemophiliacs – Menorrhagia – Recurrent epistaxis,hyphema due to ocular trauma,peptic ulcer
  23. 23. Adverse Effects • Nausea • Diarrhoea • Thromboembolic events • Disturbed colour vision • Allergic reactions • Thrombophlebitis
  24. 24. PLASMINOGEN FIBRIN FRAGMENTS FIBRIN PLASMIN ACTIVATORS INHIBITOR • Streptokinase • Urokinase • Alteplase • Reteplase • Tenecteplase • EACA • Tranexaemic acid
  25. 25. THANK YOU

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