1. Drugs Susan Louw Haematology Registrar

2. 4 Questions to ask: Can I stop? (What is the risk of thrombosis?) Should I stop? (What is the risk of bleeding?) When should I stop? Should I bridge?

3. Can I stop? What is the indication for anticoagulation? How long ago did the event occur? How serious was the event? Is life long anticoagulation indicated?

8. Should I stop? Surgery in vulnerable sites Laparoscopic surgery Extent of “trauma” Upper airway

9. When should I stop? Duration of therapeutic effect after discontinuation Onset of therapeutic effect

10. Antiplatelet agents Aspirin –“No doctor, I am on no medication…” –Commonest cause of post op wound oozing –No serious bleeding

11. Food

12. Over the counter medication

13. Anticoagulants

14. Warfarin therapy and Bleeding Most serious complication of Warfarin Most common sites of serious bleeding –GIT –Soft tissue including wounds Highest risk of bleeding: –At initiation of treatment and 1 st year thereafter –Age > 65 years –Hypertension –Alcoholism and liver disease –Hx of stroke / GIT bleeding –History of difficulty in controlling the INR –Concomittant therapy

15. Incidence of Bleeding in Warfarin therapy Fatal bleeding (Bleeding is cause of death) 0.1-1% Major bleeding (GIT, retroperitoneal, intracranial or intraoccular bleeding or any bleeding from an orifice + shock / needing transfusion or invasive procedure) 0.5-6.5% Minor bleeding6.2 - 21.8%

16. Management of Overanticoagulated Patient on Warfarin Look for and correct cause –dosing, compliance, diet, liver disease, other illnesses Management depends on –INR level –Severity of bleeding

17. Management of Overanticoagulated patient on Warfarin: No or minor Bleeding INR < 5Omit 1 Warfarin dose  INR monitoring frequency (2-3 x per wk) Resume Rx at 10-20% lower dose INR 5-9Omit 1-2 doses  INR monitoring frequency (Daily) Resume Rx at 10-20% lower dose High risk: ? Vit K 2-3 mg PO INR >9Stop Warfarin temporarily ? Vit K 3-5 mg PO Dly INR + repeat Vit K if INR not   at 24 - 48hrs Resume Rx at 20% lower dose once INR therapeutic > Frequent INR monitoring

18. Management of Overanticoagulated patient on Warfarin: Serious or life-threatening Bleeding Admit to Hospital (ICU) – urgent referral Stop Warfarin temporarily Local control of bleeding FFP / Other blood products (Recombinant Factor VIIa & Prothrombin cmplex) Vit K 5 – 10 mg slowly IV Monitor INR 6 hrly and repeat Rx

19. Dosage adjustment for patients on Warfarin maintenance INRDosage Adjustment < 1.5  wkly dose by 20% & extra dose of 20% wkly dose 1.5 - 1.9  Wkly dose by 10% 2 - 3No change 3.1-3.9 No change – recheck in 1 week. If persists,  wkly dose by 10-20% 4 - 5 Omit 1 dose &  wkly dose by 10-20%. Recheck in 2 –5 days >5See treatment of Overanticoagulated patients above

20. Vitamin K Safe / Convenient / Effective Route: –PO: preferred route –Subcut: unpredictable absorption –IM: haemorrhage –IV: SE (e.g. hypotension, chest pain) use only in emergency and give slowly Effect: –PO in 24 hrs –IV in 6 – 8 hrs May be difficult to re-anticoagulate – must give lowest dose orally Oral formulation (tablets) not available any more –give parenteral preparations orally

21. Thrombotic Complications Complication of under-warfarinisation On arterial or venous side Can occur in any organ –Brain: cerebrovascular accident (stroke) –Heart: myocardial infarction (heart attack) / malfunction of artificial heart valves –Limbs: deep vein thrombosis (PE) / gangrene Can be life-threatening

22. Thrombotic Complications: cont Management –Referral and possible admission –Anticoagulation with Heparin LMWH / UFH –Need quick onset of action –Cannot afford a hypercoagulable state Close monitoring when re-warfarinised

23. Patient Education Reason for Warfarin and duration of Rx Need to comply: dose, time of administration and testing Importance of monitoring Importance of diet Caution with all other drugs and alcohol Avoid pregnancy Warfarin side-effects (when to call a doctor) Influence of intercurrent illness