Pharmacology Anticoagulants Flashcards
Lab evaluation of clotting/haemostasis
Platelet count
Prothrombin time(PT)/ International Normalised Ratio
Activated partial thromboplastin time (APTT)
Fibrinogen test
D-dimer
Uses of PT
Monitor patients on some medications e.g Warfarin
Diagnose clotting factors - VII,V,X,II,I
Significance of prolonged PT
Deficiency in CF VII,V,X,II,I
Vit K deficiency
Liver disease
In patients with increased use of platelets - DIC/Sepsis
Normal INR
0.8-1.2
In Warfarin patients 2-3
Significance of elevated PTT
Use of anticoagulants Haemophilia Von willebrand disease anti phospholipid antibodies DI/sepsis
aPTT normal time
25-40secs
Conditions leading to high fibrinogen levels
Pregnancy
Inflammation
Infection incl. CRP
Conditions leading to low fibrinogen levels
Liver failure
DIC
Conditions leading to high D-dimer levels
Venous thromboembolism Arterial clot DIC Severe sepsis Malignancy Liver disease Surgery/trauma
Groups of drugs
Anti coagulants - suppress coagulation pathway e.g Warfarin,Heparin, N/DOAC
Antiplatelets - inhibit platelet aggregation e.g. aspirin, clopidogrel
Thrombolytics - promote lysis of fibrin strand, dissolution of thrombi e.g Alteplase (t-PA)
Warfarin
Vit K antagonists - VIII,VII
Warfarin uses
Treatment and prevention of PE, DVT
Plrevent clots in AF, RHD, prosthetic heart valves
Warfarin dosing
NTW
If rapid coagulation - 5-10mg for 2days, INR on day 3
AF - 1-2mg OD (3-4weeks to reach TW)
Maintenance - 3-9mg @same time each day
Pink - 5mg
Blue -3mg
Brown - 1mg
White -0.5mg
Monitor Warfarin
Any therapy changes ; Starting/Stopping medication e.g Erythromycin >INR, Carbamazepine/phenytoin, St John’s wort, Oral contraceptives, Mineral supplements
Side effects
Bleeding, Alopecia, vomiting, Rash, Skin necrosis, purple toes
Warfarin reversal - vit K. Fresh frozen plasma or prothrombin complex (octaplex)
