• Anticoagulants 2
    • Antiplatelets
      • NSAIDS
        • COX inhibitors but plt dysfunction resolves in 3/7 of stopping
      • Aspirin
        • Inhibits platelet PGs and thromboxane via acetylation of COX. Platelet turnover is 10% per day so plt dysfunction resolves in 7/7 or so. T1/2 20-30 mins. No need to discontinue unless high risk surgery e.g. Neuro/prostate
      • Dipyridamole
        • PDE inhibitor - no need to stop
      • Thienopyridines (clopidogrel, prasugrel and ticlopidine)
        • Blocks ADP platelet aggregation. Stop 7/7 prior to surgery. In an emergency, aprotinin and high dose steroids reduce bleeding time. 10/7 for prasugrel is recommended
        • Ticlopidine causes aplastic anaemia
      • Glycoprotein IIb/IIIa inhibitors (Tirofiban, Abciximab)
        • Abciximab (ReoPro) is a human-murine monoclonal AB which produces plt dysfunction at 50% occupancy levels. Duration of action is up to 48hrs
          Can all produce thrombocytopenia
          Also decreases fibrin levels
          Tirofiban for bridging therapy can be stopped 6-8hrs prior to CNB if to be attempted
      • Nucleotide/nucleoside analogue (Cangrelor)
        • May be used for bridging in future
          • Block ADP receptors, similar to clopidogrel
    • Oral Anticoagulants
      • Warfarin
        • Bio 100%, hepatic metabolised, effect measure by PT/INR.
        • 2.5 DVT
          2.5-3 PE, heart valves, AF, mural thrombus, Cardioversion
          3.5 recurrent DVT/PE on warfarin
        • Minor surgery
          • Reduce INR to <3
        • Major surgery
          • Heparin infusion once INR <3
            Stop heparin 4hrs pre-op
            Use UHF/LMWH until INR therapeutic
        • Convert to LMWH during pregnancy
      • Oral thrombin inhbitors
        • Dabigatran
          • 220mg/day 4 hrs after surgery for 10/7 (knee) or 28/7 (hip). Direct thrombin inhibitor
        • Rivaroxiban
          • Direct Xa inhibitor; 10mg 6-10hrs post surgery and continued for 14/7 (knee) or 35/7 (hip).
    • Guidelines
      • Drug
        • Stop before CNB/ catheter removal
          • Time interval to recommence after CNB/catheter removal
      • Aspirin/NSAIDS
        • No need to stop
          • No need to delay
      • Clopidogrel
        • 7 days prior
          • After catheter removal
      • Prasugrel
        • 10 days prior
          • 6hrs post removal
      • UFH (S/C) prophylaxis
        • 4-6 hours
          • > 1 hour
      • UFH IV (treatment)
        • Stop 2-4 hrs & check APTT
          • > 1 hour
      • LMWH (prophylaxis)
        • 12 hours
          • 2-4 hours
      • LMWH (therapeutic)
        • 24 hrs
          • 2-4 hrs
      • Fondaparinux
        • 36 hrs
          • 6 hrs post CNB, 12 hrs post catheter removal
      • Warfarin
        • INR <1.5
          • After removal
      • Dabigatran
        • Use is a CI to CNB
          • 6 hours
      • Rivaroxiban
        • 12-18 hours
          • 6 hours
    • Plt function tests
      • Aggregometry - an increase in light absorption occurs with platelet aggregation
      • TEG - newer agents can allow effects of anti platelets to be assessed
    • Parenteral anticoagulants
      • LMWH
        • 2000-10,000 Da
          Inhibit factor Xa and longer T1/2
      • UHF
        Link:HIT
        • MW 15-18,000 Da
          Binds reversibly to AATIII, accelerating its action on factors IX, X, XI, XII, plasminogen and thrombin.
          100u/kg bolus
          1000 units/hr to achieve APTT of 1.5-2.5
          T1/2 <1 hr
      • Fondaparinux
        • Xa inhibitor listened for use in major joint replacement.
      • Danaparoid
        • LMW heparinoid, a mix of heparin, dermatron and chondroitin. More selective Xa inhibitor than LMWH with a ratio of anti factor Xa to ATIII activity of 28:1 vs 3:1 with LMWH. Used in patients who develop HIT
    • CEACCP
      Link:ceaccp.oxfordjournals.org/content/7/5/157.full.pdf
    • CEACCP
      Link:ceaccp.oxfordjournals.org/content/6/4/156.full.pdf