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41 Cards in this Set
- Front
- Back
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Which clotting factors need vit K? |
II, VII, IX and X. + Protein C and protein S |
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Name some coumarins |
Warfarin, dicumarol |
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Mechanism of action of coumarins? |
They inhibit vitamin K epoxide and vitamin K reductase, decreasing the amount of usable vit K since these enzymes recycle it. The synthesis of clotting factors II, VII, IX and X + protein C and S decreases |
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How fast is the action of coumarins? |
They are slow because their effect is functioning clotting factors needs to be eliminated. Takes 4 days. |
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When are coumarins indicated? |
- Atrial fibrillation - Artificial heart valve - DVT prophylaxis |
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Pharmacokinetics of coumarins? |
They have good oral absorption, strong plasma protein binding (97%) and are inactivated by CYP450 in the liver. |
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Why must the effect of coumarins be monitored, and how? |
People respond differently to the same dose, so it is important to start with a low dose. INR of patient should be measured often and should be between 2 and 3. |
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When are coumarins contraindicated? |
In pregnancy (teratogenic), liver and kidney failure. |
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Which drugs can decrease effect of coumarins? |
Vitamin K and drugs that induce CYP450 |
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Mechanism of action of unfractionated heparin? |
It increases the effect of Antithrombin III, which is an endogenous molecule that inactivates factors XIIa, XIa, IXa, Xa and IIa. |
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How is heparin administered? |
The size is large, so it is given IV or subcutaneously. Immediate onset with IV, and 60 mins subcutaneous. |
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Indications of heparin? |
Same as coumarins but when the effect is needed acutely. |
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What should be measured when giving a patient heparin, and what should be the target value? |
Activated partial thromboplastin time (APTT). The target value should be 2 - 3 x a healthy control. |
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Is heparin safe during pregnancy? |
Yes |
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What is the antidote for heparin? |
Protamine sulphate |
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Side effects of heparin? |
Heparin-induced thrombocytopaenia and thrombosis. Occurs if IgG and IgM antibodies against heparin and platelet factor 4 are produced. |
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What are low molecular weight heparins? |
Fragments of regular, unfragmented heparin which are more predictable than regular heparin. |
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Name low molecular weight heparins |
Enoxaparin, dalteparin and fondaparinux. |
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Why are low molecular weight heparins preferred over unfractionated heparin? |
LMWH have longer half-time and they do not require routine blood tests every day or being administrated more often than 1-2 times a day so patients can inject themselves. |
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Which coagulation factors do the low molecular weight heparins inhibit? |
Only Xa. |
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Pharmacokinetics for low molecular weight heparins? |
Renal excretion, so should not be given to someone with renal failure. |
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What are direct acting oral anticoagulants? |
Recent anticoagulants, which do not need monitoring. They directly inhibit clotting factors |
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Name a direct acting oral anticoagulant which inhibits IIa (thrombin)? |
Dabigatran |
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Name some direct-acting oral anticoagulants which inhibit factor Xa? |
Rivaroxaban, apixaxaban, edoxaban. |
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Mechanism of action of aspirin (acetylsalicylic acid)? |
Inhibits cyclooxygenase 1 enzyme, which produces thromboxanes. By reducing the amount of thromboxane A2 in thrombocytes, aspirin interferes with platelet activation and aggregation. |
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When is aspirin indicated? |
AMI Ischaemic stroke Angina pectoris After coronary intervention Prevention of cardiovascular disease Prevention of colorectal cancer Peripheral artery disease |
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Side effects of aspirin? |
- Reye syndrome, encephalopathy, in children when taken during viral infection - Peptic ulcer - Aspirin asthma |
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Mechanism of action of P2Y12 blockers? |
Inhibit P2Y12 receptor, found on platelets. This prevents platelet aggregation because the receptor binds usually to ADP from other activated platelets. |
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Mechanism of action of glycoprotein IIb/IIIa inhibitors |
Bind to and inhibit receptor glycoprotein IIB/IIIA, preventing platelets to bind to each other and aggregate. |
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Name Glycoprotein IIb/IIIa inhibitors |
Abciximab, eptifibatide, tirofiban |
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What are anticoagulants used for mostly? |
Prevention of DVT and other venous thrombosis (due to stasis) |
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What are anti-platelet drugs mostly used for? |
Acute treatment for coronary syndromes like NSTEMI, STEMI, unstable angina, phrophylaxis of acute coronary syndromes and cerebral stroke and in patients with stents. |
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What is the treatment for heparin induced thrombocytopaenia? |
HIT is treated by taking the patient off heparins and giving another anticoagulant instead (not warfarin). |
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What are the advantages of LMWH compared to unfractionated heparin? |
- No monitoring necessary - Patients can be taught to inject themselves subcutaneously - Lower risk of bleeding and HIT |
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What are the disadvantages of LMWH compared to unfractionated heparin? |
LMWH are excreted renally so they can't be used in renal failure. |
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What are the advantages of DOACs compared to other anticoagulants? |
- Don't require regular monitoring - Can be taken orally |
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What are the disadvantages of DOACs compared to other anticoagulants? |
- Antidotes are expensive and not readily available - Should be used with care in people with liver or kidney failure |
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Name some P2Y12 receptor antagonists |
Clopidogrel, prasugrel, ticagrelor |
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What are the indications for Glycoprotein IIb/IIIa inhibitors? |
High-risk patients before and during coronary intervention |
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What is the antidote of dabigatran? |
Idarucizumab |
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What is the antidote of apixaban and rivaroxaban? |
Andexanet |
