Anticoagulants

Question 1

Classify anticoagulants

Answer 1

1. used in vitro used
2. in vivo -
   a)parental anticoagulants -
   i) Indirect thrombin inhibitor’s
   ii) direct thrombin inhibitor’s
   b)oral anticoagulants -
   i)coumarin derivatives 
   ii) indandione derivatives
   iii)direct thrombin inhibitor
   iv)factor Xa inhibitor

Question 2

Name in vitro Anticoagulant drugs

Answer 2

1. Heparin
2. sodium citrate
3. sodium oxalate
4. sodium edetate

Question 3

Name in the Vivo parental indirect thrombin inhibitor‘s

Answer 3

1. Unfractionated heparin
2. low molecular weight heparin‘s
3. synthetic

Question 4

Name low molecular weight heparin

Answer 4

1. Enoxaparin
2. Dalteparin 
3. Tinzaparin
4. Ardeparin
5. Reviparin

Question 5

Name a synthetic parenteral anticoagulant in vivo thrombin inhibitor

Answer 5

Fondaparinux

Question 6

Name parental anticoagulants in vivo that are direct thrombin inhibitor’s

Answer 6

1. Lepirudin
2. bivalirudin
3. Argatroban

Question 7

Name anticoagulant used orally in vivo Coumarin derivatives

Answer 7

1. Warfarin 
2. Dicumarol
3. Acenocoumarol

Question 8

Name indandione derivatives

Answer 8

Phenindione 

Question 9

Name oral anticoagulants that can be used in vivo that are direct thrombin inhibitor’s

Answer 9

Dibigatran

Question 10

Name factor Xa inhibitor

Answer 10

Rivaroxaban

Question 11

What is the mechanism of action of heparin

Answer 11

1. Forms of complex with plasma antithrombin III
2. Inhibits factors Xa, IIa , IXa, XIa, XIIa, XIIIa.
3. Binds to thrombin and antithrombin
4. low concentration, inhibits conversion of prothrombin to thrombin
5. high doses, antiplatelet action
6. releases lipoprotein lipase which hydrolyzes triglycerides

Question 12

Why is heparin not used intramuscularly

Answer 12

It can cause a haematoma

Question 13

If life-threatening haemorrhage occurs, which heparin antagonist/drug should be used to neutralize the effect

Answer 13

Protamine sulphate [strong base]

Question 14

How much milligrams of protamine sulphate is needed to neutralize 100 units of heparin

Answer 14

1 mg

Question 15

How does heparin induced thrombocytopenia in in which molecule is incidence higher

Answer 15

Formation of antibodies against platelet factor four – heparin complex
Incidence is higher in unfractioned heparin

Question 16

What are the adverse effects of heparin

Answer 16

1. Bleeding
2. heparin induced thrombocytopenia
3. hypersensitivity reactions
4. osteoporosis
5. reversible alopecia
6. abnormalities in liver function

Question 17

What are some contraindications of heparin 

Answer 17

1. Hemophiliacs
2. patients with heparin induced thrombocytopenia
3. severe hypertension
4. intracranial haemorrhage
5. bacterial endocarditis
6. active TB 
7. Peptic ulcer
8. threatened abortion
9. cirrhosis
10. renal failure

Question 18

How do low molecular weight heparin’s prevent coagulation

Answer 18

By inhibiting factor Xa through antithrombin

Question 19

What are the advantages of molecular weight heparin

Answer 19

1. Higher subcutaneous bioavailability then UFH
2. Longer half life
3. They do not require aPTT monitoring
4. lower incidence of thrombocytopenia and osteoporosis as compared to UFH

Question 20

What are the uses of fondaparinux

Answer 20

They’re used for
1. pulmonary embolism
2. deep vein thrombosis

Question 21

Which Drugs can be used as an anticoagulant in patients with heparin induced thrombocytopenia

Answer 21

Parental direct thrombin inhibitors
1. Lepirudin
2. Agratroban

Question 22

What is the mechanism of action of warfarin

Answer 22

Warfarin competitively inhibits the synthesis of vitamin K dependent factors - II, VII, IX, and X - by inhibiting epoxide reductase enzyme

Question 23

What is the duration of anticoagulant effect of warfarin

Answer 23

It depends on the half-lives of clotting factors. Over a period of 1 to 3 days

Question 24

What is the treatment of overdosage on warfarin

Answer 24

Fresh frozen plasma and vitamin K1

Question 25

What are the adverse effects of warfarin/oral Anti-coagulants

Answer 25

1. Bleeding 2. teratogenic effect 3. skin necrosis 4. others: diarrhea, alopecia, urticaria, dermatitis, abdominal cramps and anorexia.

Question 26

What are the drugs or Warfarin/anticoagulants Cannot be taken with

Answer 26

1. Cholestyramine 2. barbiturates/carbamazepine/rifampicin 3. oral contraceptives 4. phenytoin/sulfonamines  5. erythromycin/metronidazole 6. tetracyclines 7. aspirin another NSAIDs 8. Cefoperfazone/ceftriaxone

Question 27

What is the interaction between warfarin and cholestyramine

Answer 27

Reduced absorption of warfarin

Question 28

What is the interaction between oral coagulants and barbiturates/carbamazepine/rifampicin

Answer 28

they are enzyme inducers, increase metabolic clearance of oral coagulants and decrease anticoagulant effect

Question 29

What is the effect of taking warfarin and oral contraceptives together

Answer 29

Level of Clotting factors increase Leading to Decreased anticoagulant affect

Question 30

What is the interaction between warfarin and phenytoin/suulfonamides

Answer 30

The displace war friend from plasma protein binding site and increase free plasma concentration of warfarin, can lead to bleeding

Question 31

What is the interaction between warfarin and erythromycin/metronidazole

Answer 31

Decrease were Warfarin Clearance and increase anticoagulant affect

Question 32

What is the interaction between warfarin and tetracyclines

Answer 32

They suppress bacterial flora and decrease vitamin K production, leading to increase warfarin affect

Question 33

What is the interaction between warfarin and ceftriaxone/Cefoperazone

Answer 33

Severe bleeding can occur due to hypoprothrombinaemia

Question 34

What is the interaction between warfarin and aspirin and other NSAIDs 

Answer 34

NSAID have an anti-platelet effect, displace warfarin plasma protein and potentiate warfarin affect