Anticoagulation

Question 1

What is direct at inhibitors

Answer 1

Reversible inhibits thrombin - lepirudin, dabigatran

Question 2

Warfarin

• moa
• SE
• cautions

Answer 2

Moa: inhibit synthesis of vit k dependent clotting factors (2,7,9,10) and anti thrombotic factors protein C and s via inhibit gamma glutamyl carboxylase and vit k reductase

SE: bleeding, skin necrosis, hepatic dysfunction

Target INR 2-3, start with heparin to bridge to warfarin as take effect in 2-3 days, stop warfarin 4-5 days before surgery, allow INR to return to normal

P450 inhibitors- decrease warfarin, increase INR
Qaam: Quinolones, macrolides, antiarrhythmics, Azoles

P450 inducers - increase warfarin, decrease INR
- anti epileptics, sjw, rifampicin

Precautions

Question 3

Thrombolytic
- type
- moa
- SE
- cautions
CI

Answer 3

Types
- streptokinase, alteplase, reteplase, urokinase

Moa - convert plasminogen to plasmin (catalyse breakdown of fibrin)

SE - severe bleed, nephritis, vasculitis,

CI:
Absolute
- haemorrhagic stroke, active bleed, sx 180/110 on 2 readings, intra ocular bleed, severe renal/liver disease, warfarin, stroke > 12 months, CPR

Question 4

Heparin and LMWH
- moa
- dose and type
- SE
- vs
-

Answer 4

Example
- dalteparin or enoxaparin (LMWH)

Moa
- inactivate clotting factor iia (thrombin) and Xa by binding to anti thrombin III and potentiate it
- LMWH more on Xa
Prevent fibrinogen to fibrin

SE:
Bleeding, hyperkalaemia, thrombocytopenia, skin necrosis at site, hit (leads to thrombosis and ischaemia, stop and give lepuridin due to anatibodies to heparin bound platelet factor 4)

Heparin vs LMWH

• LMWH: more predictable, less serve hit, 1/2 life is 3-6 hours, more costly useful in ortho, last 36 hours, renal failure
• heparin: less predictable, more severe hit, safe in renal impairment, 1/2 life 60min, reversible with protamine sulfate

Dose

• LMWH is sc and heparin sc/IV
• heparin sc 5000u 2 hours before procedure, 2-3x daily (IV bolts 80u/kg)

Monitor: APTT, UEC, LFT, FBC (platelet)