Doses - HEPARIN SODIUM, HEPARIN CALCIUM
Doses of heparin are controversial; dosage ranges and methods may vary widely depending on the clinician/author. Refer to the actual references for these doses for more complete information.Dogs & Cats:
For adjunctive treatment of DIC: Note: Heparin therapy may be only one aspect of successfultreatment of DIC. Alleviation of the precipitating cause, administration of fluids, blood, aspirin, and diligent monitoring of coagulation tests (APTT, PT), fibrin degradation products, andfibrinogen may all be important factors in the treatment of DIC.
a) 75 Units/kg SQ tid (Wingfield and Van Pelt 1989)
b) Add 5, 000 U of heparin/500 ml warmed whole blood 30 minutes before transfusion.
Alternatively, give 10 - 150 U/kg SQ q12h. Heparin must be tapered over 48 hours or a"rebound effect" may occur. (Feldman 1985)
c) After pH has been corrected and perfusion maximized, transfuse heparinized wholefresh blood or plasma (75 U/kg heparin) one time. Then begin mini-dose heparintherapy at 5 - 10 U/kg/hour by continuous IV infusion or 75 U/kg SQ q8h. Continuewithout interruption until DIC has completely disappeared. With these doses, bleedingrisk is negligible and APTT monitoring not necessary, although thrombocytopenia maydevelop. (Slappendel 1989)
d) Before administering heparin, provide sufficient fresh whole blood to maintain plateletcounts above 30, 000/microliter and fibrinogen levels over 50 mg/dl. Then give heparin at50 - 100 U/kg SQ q6h. Alternatively, dose heparin sufficiently to increase APTT to 1.5-2 times normal (may be more effective in patients susceptible to thromboembolization).(Green 1989) For adjunctive treatment of thromboembolic disease:
a)Dogs:
500 Units/kg q8h SQ
Cats: 250-375 U/kg q8h SQ; adjust dose frequently by monitoring APTT to 1.5-2.5times normal (control). (Roudebush 1985)
b) For feline aortic thromboembolism: 220 U/kg IV, followed by 66 U/kg SQ 3 hours laterand then give SQ 4 times daily. Adjust SQ heparin dose so that clotting time is 2-2.5times normal. (Harpster 1986)
c) For arterial thromboembolism; pulmonary thromboembolism: Initially, 200 U/kg IV, then 50 - 10 U/kg SQ tid-qid. Adjust dose to prolong PTT or ACT to 2-2.5 timesnormal. (Harpster 1988), (Bauer 1988)
d) For feline thromboembolic disease associated with cardiomyopathy: Initially, heparin at1000 U IV, then 50 U/kg SQ 3 hours later and repeated at 6-8 hour intervals. Adjustdose to prolong clotting time to 2-2.5 times pretreatment baseline index value. (Fox1989)
e) For canine arterial thrombosis and thromboembolism: Keep dog in a quiet and warmplace; give analgesics if necessary. Give heparin initially at 220 U/kg IV. Correct dehydration and dilute blood by administering electrolyte solutions. Dextran products maybe helpful. Follow-up doses of heparin should be started low and increased until APTTis 2-2.5 times normal. After 3-5 days of therapy, gradually reduce heparin over 48-72hours while dog is put on oral anticoagulant therapy (see warfarin monograph). (Suter 1989)
To prevent clots forming when performing closed chest lavage with pyothorax:
a) Add 1000 U of heparin per liter of lavage fluid (warm normal saline). This fluid isinstilled at 20 ml/kg bid for 5-7 days. Antibiotics (often penicillin) or enzymes (e.g., streptokinase) may also be added to fluid. (Berkwitt and Berzon 1988)
For adjunctive therapy of acute complicated or severe pancreatitis in dogs:
a) 50 - 75 U/kg SQ bid-tid; may reduce thromboembolic tendencies, but efficacy is unknown and heparin is not indicated in all cases. (Bunch 1988)
For detection of lipoprotein lipase activity (heparin stimulation test):
a) Measure serum lipids just before and 15 minutes after heparin at 100 U/kg IV. Lack ofincrease in lipolytic activity is suggestive of lipoprotein lipase deficiency. (Kay, Kruth, and Twedt 1988)
For adjunctive therapy of severe thermal burns:
a) 100 - 200 U/kg IV for 1-4 doses; routine use is of questionable value. Select patientsbased on individual considerations. (Morgan 1988)Horses:
For adjunctive treatment of DIC: Note: Heparin therapy may be only one aspect of successfultreatment of DIC. Alleviation of the precipitating cause, administration of fluids, blood, aspirin, and diligent monitoring of coagulation tests (APTT, PT), fibrin degradation products, andfibrinogen may all be important factors in the treatment of DIC.
a) 80 - 100 U/kg IV q4-6h (may be added to fluids and given as a slow drip). Low grade
DIC may be treated with 25 - 40 U/kg SQ 2-3 times a day. (Byars 1987)
As adjunctive therapy in endotoxic shock:
a) 40 Units/kg IV or SQ 2-3 times a day may prevent the development of microthrombi;additional studies required to confirm positive benefits. (Semrad and Moore 1987)
Monitoring Parameters - Note: The frequency of monitoring is controversial and is dependent onseveral factors, including heparin dose, patient's condition, concomitant problems, etc. Because ofthe high incidence of hemorrhage associated with heparin use, frequent monitoring of APTT isessential early in therapy (particularly using higher dosages) and in critically ill animals.1) While whole blood clotting time (WBCT), partial thromboplastin time (PTT) and activated partial thromboplastin times (APTT) may all be used to monitor therapy, APTT is most often recommended. 2) Platelet counts and hematocrit (PCV) should be done periodically 3) Occult blood in stool and urine; other observations for bleeding 4) Clinical efficacy
Client Information - Because of the intense monitoring necessary with heparin's use and theserious nature of the disease states in which it is used, this drug should be utilized only by professionals familiar with it and, preferably, in an inpatient setting.
Dosage Forms/Preparations/FDA Approval Status/Withholding Times - Veterinary-Approved Products: None located.
U/ml, 40, 000 U/ml in 0.5, 1, 2, 4, 5, 10, and 30 ml amps and multi-dose vials (depending onconcentration and manufacturer).
Also available for heparin sodium are pre-filled syringes in various concentrations and amounts, and premixed in normal saline and half-normal saline in 250 ml, 500 ml and 1000 mlcontainers.
Dogs & Cats: 
For adjunctive treatment of DIC: Note: Heparin therapy may be only one aspect of successfultreatment of DIC. Alleviation of the precipitating cause, administration of fluids, blood, aspirin, and diligent monitoring of coagulation tests (APTT, PT), fibrin degradation products, andfibrinogen may all be important factors in the treatment of DIC. a) 75 Units/kg SQ tid (Wingfield and Van Pelt 1989)
b) Add 5, 000 U of heparin/500 ml warmed whole blood 30 minutes before transfusion.
Alternatively, give 10 - 150 U/kg SQ q12h. Heparin must be tapered over 48 hours or a"rebound effect" may occur. (Feldman 1985)
c) After pH has been corrected and perfusion maximized, transfuse heparinized wholefresh blood or plasma (75 U/kg heparin) one time. Then begin mini-dose heparintherapy at 5 - 10 U/kg/hour by continuous IV infusion or 75 U/kg SQ q8h. Continuewithout interruption until DIC has completely disappeared. With these doses, bleedingrisk is negligible and APTT monitoring not necessary, although thrombocytopenia maydevelop. (Slappendel 1989)
d) Before administering heparin, provide sufficient fresh whole blood to maintain plateletcounts above 30, 000/microliter and fibrinogen levels over 50 mg/dl. Then give heparin at50 - 100 U/kg SQ q6h. Alternatively, dose heparin sufficiently to increase APTT to 1.5-2 times normal (may be more effective in patients susceptible to thromboembolization).(Green 1989) For adjunctive treatment of thromboembolic disease:
a)
Dogs:
500 Units/kg q8h SQ Cats: 250-375 U/kg q8h SQ; adjust dose frequently by monitoring APTT to 1.5-2.5times normal (control). (Roudebush 1985)
b) For feline aortic thromboembolism: 220 U/kg IV, followed by 66 U/kg SQ 3 hours laterand then give SQ 4 times daily. Adjust SQ heparin dose so that clotting time is 2-2.5times normal. (Harpster 1986)
c) For arterial thromboembolism; pulmonary thromboembolism: Initially, 200 U/kg IV, then 50 - 10 U/kg SQ tid-qid. Adjust dose to prolong PTT or ACT to 2-2.5 timesnormal. (Harpster 1988), (Bauer 1988)
d) For feline thromboembolic disease associated with cardiomyopathy: Initially, heparin at1000 U IV, then 50 U/kg SQ 3 hours later and repeated at 6-8 hour intervals. Adjustdose to prolong clotting time to 2-2.5 times pretreatment baseline index value. (Fox1989)
e) For canine arterial thrombosis and thromboembolism: Keep dog in a quiet and warmplace; give analgesics if necessary. Give heparin initially at 220 U/kg IV. Correct dehydration and dilute blood by administering electrolyte solutions. Dextran products maybe helpful. Follow-up doses of heparin should be started low and increased until APTTis 2-2.5 times normal. After 3-5 days of therapy, gradually reduce heparin over 48-72hours while dog is put on oral anticoagulant therapy (see warfarin monograph). (Suter 1989)
To prevent clots forming when performing closed chest lavage with pyothorax:
a) Add 1000 U of heparin per liter of lavage fluid (warm normal saline). This fluid isinstilled at 20 ml/kg bid for 5-7 days. Antibiotics (often penicillin) or enzymes (e.g., streptokinase) may also be added to fluid. (Berkwitt and Berzon 1988)
For adjunctive therapy of acute complicated or severe pancreatitis in dogs:
a) 50 - 75 U/kg SQ bid-tid; may reduce thromboembolic tendencies, but efficacy is unknown and heparin is not indicated in all cases. (Bunch 1988)
For detection of lipoprotein lipase activity (heparin stimulation test):
a) Measure serum lipids just before and 15 minutes after heparin at 100 U/kg IV. Lack ofincrease in lipolytic activity is suggestive of lipoprotein lipase deficiency. (Kay, Kruth, and Twedt 1988)
For adjunctive therapy of severe thermal burns:
a) 100 - 200 U/kg IV for 1-4 doses; routine use is of questionable value. Select patientsbased on individual considerations. (Morgan 1988)
Horses: 
For adjunctive treatment of DIC: Note: Heparin therapy may be only one aspect of successfultreatment of DIC. Alleviation of the precipitating cause, administration of fluids, blood, aspirin, and diligent monitoring of coagulation tests (APTT, PT), fibrin degradation products, andfibrinogen may all be important factors in the treatment of DIC. a) 80 - 100 U/kg IV q4-6h (may be added to fluids and given as a slow drip). Low grade
DIC may be treated with 25 - 40 U/kg SQ 2-3 times a day. (Byars 1987)
As adjunctive therapy in endotoxic shock:
a) 40 Units/kg IV or SQ 2-3 times a day may prevent the development of microthrombi;additional studies required to confirm positive benefits. (Semrad and Moore 1987)
Monitoring Parameters - Note: The frequency of monitoring is controversial and is dependent onseveral factors, including heparin dose, patient's condition, concomitant problems, etc. Because ofthe high incidence of hemorrhage associated with heparin use, frequent monitoring of APTT isessential early in therapy (particularly using higher dosages) and in critically ill animals.
Client Information - Because of the intense monitoring necessary with heparin's use and theserious nature of the disease states in which it is used, this drug should be utilized only by professionals familiar with it and, preferably, in an inpatient setting.
Dosage Forms/Preparations/FDA Approval Status/Withholding Times - Veterinary-Approved Products: None located.
Human-Approved Products:
Heparin Sodium Injection 1000 U/ml, 2000 U/ml, 2500 U/ml, 5000 U/ml, 10, 000 U/ml, 20, 000U/ml, 40, 000 U/ml in 0.5, 1, 2, 4, 5, 10, and 30 ml amps and multi-dose vials (depending onconcentration and manufacturer).
Also available for heparin sodium are pre-filled syringes in various concentrations and amounts, and premixed in normal saline and half-normal saline in 250 ml, 500 ml and 1000 mlcontainers.