Heparin Pharmacology

Heparin

About Heparin
A highly-sulfated glycosaminoglycan, Anticoagulant.
Mechanism of Action of Heparin
The anticoagulant action of heparin is exerted through affecting conversion of fibrinogen to fibrin mediated by factors Xa as well as IIa. It acts by activating plasma antithrombin III (AT III). The heparin-AT III complex then binds to and inactivates clotting factors ;.( Xa, IIa, IXa, XIa, and XIIIa) of the intrinsic and common pathways but not factor VIIa operative in the extrinsic pathway. At lower concentrations it selectively inhibits factor Xa mediated conversion of Prothrombin to thrombin. At lower concentrations it inhibits intrinsic pathway of coagulation but at higher concentration it also interfere with common pathway. At higher doses it prevents platelet aggregation.
Pharmacokinets of Heparin
Absorption: It is not absorbed orally should be given parenterally.
Distribution: Distributed in a plasma protein bound form. Does not cross Placental barrier and blood brain barrier.
Metabolism: Drug is removed by reticuloendothelial system and a small portion is metabolized in liver.
Excretion: Excreted as fragments in urine.
Onset of Action for Heparin
I.V.: Rapid
S.C.: 60minutes
Duration of Action for Heparin
4 to 12 hours
Half Life of Heparin
1 to 2 hours
Side Effects of Heparin
1. Haemorrhage
2. Haematuria
3. Prolonged clotting time
4. Thrombocytopenia
5. Irritation
6. Pain
7. Haematoma
8. Ulceration
9. Necrosis
10. Hypersensitivity reactions
11. Urticaria
12. Rash
13. Anaphylaxis
14. Osteoporosis
15. Hyper kalaemia
16. Reversible alopecia

Contra-indications of Heparin
1. Hypersensitivity to the drug
2. Bleeding disorders
3. Thrombocytopenia
4. Ulceration of gastrointestinal tract
5. In sub acute bacterial endocarditis
6. Severe hypertension
7. Shock
8. Open ulcerative wounds
9. Extensive denudation of skin
10. Increased capillary permeability
11. Chronic alcoholics
12. Renal impairment
13. During or after brain, eye and spinal cord surgery
14. Threatened abortion

Special Precautions while taking Heparin
1. Along with Aspirin or other antiplatelet drugs
2. Hepatic diseases
3. Renal diseases
4. In postpartum women and women during menses
5. Asthma
6. Alcoholism
7. Allergies
8. Monitor bleeding disorders prior to therapy.
Pregnancy Related Information
Use with caution
Old Age Related Information
Use with caution
Breast Feeding Related Information
May be used
Children Related Information
Use with caution
Indications for Heparin
1. Deep vein thrombosis
2. Pulmonary embolism
3. Intravascular coagulation
4. Peripheral arterial embolism
5. Atrial fibrillation with embolism
6. Venous thrombosis

Interactions for Heparin
Cephalosporins: Increased risk of bleeding.
Nitroglycerin: Efficacy of heparin may be decreased.
Penicillins: Additive effects with heparin, increased risk of bleeding.
Salicylates and dipyridamole: Increased risk of bleeding.
Digitalis, tetracyclines, antihistamines: May partially inhibit the anticoagulant effect of heparin.
Lab. Tests: Significant elevation of aminotransferase (AST & ALT) levels, errors in measurements of carbon dioxoide pressure, bicarbonate concentration and base excess may occur when sample for gas analysis contains 10% or more of heparin.
Typical Dosage for Heparin
Deep Sub cutaneous administration: 10000 to 20000 Units S.C.; Prior to this; administer 5000 units intravenously. Then continue the therapy 8th hourly with 8000 to 10000 units administration of concentrated solution subcutaneously at different sites.
I.V.: 10000units intravenously. Then 5000 to 10000units 4 to 6 times daily.
I.V. infusion: Starts with 5000 units I.V. injection. Then 20000 to 40000 units/day in 1,000ml of 0.9% sodium chloride or other compatible solution for infusion.
Children: 50 units/kg (I.V. drip),Maintenance dose: 100 units/kg (I.V. drip) 6 times daily.

Schedule of Heparin
H
Storage Requirements for Heparin
Store at controlled room temperature at a range of 20 to 25 degree C.
Effects of Missed Dosage of Heparin
Take the missed dose as soon as noticed and if it is the time for next dose then skip the missed dose. Continue the regular schedule. Do not double the dose.
Effects of Overdose of Heparin
Immediately stops the drug during over dosage. In severe haemorrhage treat with Protamine sulfate. 1mg Protamine sulfate neutralizes 90 units of bovine heparin or 115 units of porcine heparin. Give Protamine slowly by I.V. injection over 3minutes. (No more than 50mg should be given in any 10minutes). For severe bleeding blood transfusion is required.

Home Delivery for Heparin in Your City

Medicine India is just a publishing medium for medicine related information and does not provide services or sales of medicines including heparin.

However, we do publish a comprehensive directory of Pharmacies, Chemists and Druggists in cities all over India. You can use this directory to find the medicine stores in your city (or area) that provide home delivery services for heparin and other medicines and health products. Home delivery services for heparin may be free or they may cost you depending on the pharmacy and the minimum order requirements. It would be best to get this clarified while placing the order.

Please be aware that you should take heparin only if a doctor has recommended or prescribed it. Some or all pharmacies who provide a home delivery service for medicines might insist on a prescription for heparin before they complete the sale. You can get this information while placing the order for heparin with the pharmacy.

Heparin is a generic medicine name and there are several brands available for it. Some of the brands for heparin might be better known than heparin itself. If the pharmacy that's willing to deliver medicines to your home doesn't have heparin in stock, you can ask for one of the branded alternatives for heparin.