Anticoagulation – ( Pharmacology)


Drugs that prevent blood coagulation and stop the occurrence or expansion of a thrombus.


1. Vitamin K antagonist – Warfarin.

2. Heparin and related drugs:

(a) Heparin.

(b) LMWH (Enoxaparin, Dalteparin, Tinzaparin).

(c) Synthetic heparin derivatives (Fondaparinux – longer acting).

3. Direct thrombin inhibitors:

(a) Parenteral → Hirudin, Lepirudin, Argatroban, Bivalirudin.

(b) Oral → Dabigatran.

4. Active factor Xa inhibitor → Rivaroxaban, Apixaban.


  • Competitively inhibits vitamin K epoxide reductase and inhibits the post-translational carboxylation of glutamate residues on vitamin K dependent coagulation factors II (prothrombin), VII, IX, and X.
Warfarin - Anticoagulation


  • Antithrombin III-Irreversibly inactivates thrombin and factor Xa.
  • Heparin potentiates anti-thrombin III activity.

Advantages of LMWH:

1. Can be administered s.c.

2. Effects are consistent and dosing less frequent (Long t1/2 and eliminate. By 1st order kinetics).

3. Dose is given in mg (not in units) can be easily calculated on a bodyweight basis.

4. Chance of hemorrhage is less.

5. Risk of osteoporosis is decreased.

Route of administrationI.v., S.c.Oral
Onset of actionImmediateDelayed
MechanismActiv. Of AT-IIIDecrease activ. Of c.f. 2,7,9,10
AntagonistProtamine sulphateVitamin K
UseTo initiate therapyFor maintenance

Uses of anti-coagulants:

1. Myocardial infarction

2. Unstable angina

3. Rheumatic heart disease

4. Cerebrovascular disease

5. Haemodialysis

6. Defibrination syndrome (DIC).

Make sure you also check our other amazing Article on : Coagulants
Sharing Is Caring:

Leave a Comment