DESCRIPTION:
Heparin is an anticoagulants. It is a non-uniform mixture of straight chain mucopolysaccharides with molecular weight 10,000 to 20,000.
Heparin present in all tissue containing mast cell like lung liver, intestinal mucosa.
It is produced from ox lung & pig intestinal mucosa.
MECHANISM OF ACTION:
It acts as anticoagulants. It acts indirectly by activating plasma thrombin III(which is A III, a serine proteniase inhibitor).
It makes complex than binds to clotting factor of the intrinsic pathway (Xa, IIa,IXa XI a, XII-a ,) & inactives them.
It is not operative extrinsic pathway.
Xa is responsible for conversion of fibrinogen to fibrin.
At higher dose it ,inhibit platelet aggregation and prolongs bleeding time.
PHARMACOLOGY:
Heparin is a large ionized molecules. So it is not absorbed orally.
I.V dose of heparin is acts immediately (~60 min). It is anticoagulant of choice during pregnancy.
Metabolized in liver by heparinise excreted in urine.
Half Life: 1-4 hrs.
THERAPEUTIC USES:
Heparin is generally used for anticoagulate for the following conditions :-
• Acute coronary syndrome
• Atrial fibrillation
• Cardiopulmonary bypass for heart surgery
• Hemolfiltration
• Deep vein thrombosis & Pulmonary embolism
ADVERSE EFFECTS :
• Haematuria ( due to presence of blood in urine)
• Thrombocytopenia (due to deficiency of platelets in the blood)
REFERENCE- Tripathi K.D. "Essentials of Medical Pharmacology", 7th Edition, page no- 617
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