Heparin

Whats Heparin:

Heparin is an anticoagulant (blood thinner) that prevents the formation of blood clots.

Heparin is used to treat and prevent blood clots in the veins, arteries, or lung. Heparin is also used before surgery to reduce the risk of

blood clots

Heparin – the molecule

heparin is heterogeneous of un branched polysaccharide chains

Alternating monosaccaride units of L-iduronic acid and D-glucosamine

one third of the polysaccharide chain contain a specific antithrombin binding pentasaccharide sequence

Heparin – the source

preparation from porcine and bovine intestinal mucous

- preparation from bovine lung

Mechanism of action :

Heparin exerts parts of its anticoagulant activity through interaction with antithrombin

antithrombin binds specifically to a pentsaccharide in heparin

binding to heparin induced a conformational change in the antithrombin , which accelerate enzyme inhibition

Forms of heparin :

1- unfractionated heparin (UF)

2- low molecular weight heparin (LMW)

Trade Names

. Heparin Sodium

. Heparin I.V. Flush

. Monoject PreFill Advanced (this form of heparin must not be used to treat or prevent blood clotting in the body )

Pharmacokinetics:

Absorption: Heparin is not absorbed from GI; must be given IV or subcutaneously,

Metabolism: The liver andreticuloendothelial system are the sites of biotransformation.

Elimination: The average half-life is 1.5 h (range, 1 to 6 h) and is dose dependent Excreted in the urine

Indications and Usage:

- Prophylaxis and treatment of venous thrombosis and it extensions

- pulmonary embolism (PE), peripheral arterial embolism, and atrial fibrillation with embolization.

- treatment of acute and chronic consumption coagulopathies (disseminated intravascular coagulation [DIC])

- prevention of postoperative deep venous thrombosis

- Also used to maintain catheter patency and as an anticoagulant in blood transfusions, extracorporeal circulation, dialysis, and laboratory samples.

Dosage and Administration:

- intravenously (immediate effect) - 20 to 40 thousands units/day dose

- subcutaneously ( effect on 20-60 min ) -8,000 to 10,000 units every 8 h .

Contraindications :

- Severe thrombocytopenia

- Patients in whom suitable blood coagulation tests cannot be performed.

- Hypersensitivity to heparin or any other product ingredients.

- do not administer products containing benzyl alcohol as a perseverative to neonates, infants, pregnant women, or breast-feeding women

- Patients with hypersensitivity to corn products and bisulfites (may be contained in some heparin sodium in dextrose 5% 

Drug interactions

interaction with :

- Alteplase

- Antihistamines

- Antithrombin

- Cephalosporins (eg, cefazolin, ceftriaxone)

- Penicillins, parenteral (eg, ampicillin, penicillin G)

Adverse Reactions

-Hematologic:Hematologic side effects including hemorrhage at any site have been reported the most frequently.

-Cardiovascular:Cardiovascular side effects have included new or recurrent arterial and venous thrombosis in association with thrombocytopenia.

-Dermatologic:Dermatologic side effects have included extensive skin necrosis, necrotic lesions at subcutaneous injection sites

-Musculoskeletal : Musculoskeletal side effects have

included osteoporosis

-Endocrine: Endocrine side effects have included increased free thyroxine levels. Acute adrenal insufficiency caused by heparin induced adrenal hemorrhage has been reported

Thank you