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Heparin (Heparin Sodium) - Warnings and Precautions

 
 



WARNINGS

Heparin is not intended for intramuscular use.

Fatal Medication Errors

Do not use Heparin Sodium Injection as a ‘‘catheter lock flush’’ product.  Heparin Sodium Injection is supplied in vials containing various strengths of heparin, including vials that contain a highly concentrated solution of 10,000 units in 1 mL.  Fatal hemorrhages have occurred in pediatric patients due to medication errors in which 1 mL Heparin Sodium Injection vials were confused with 1 mL ‘‘catheter lock flush’’ vials.  Carefully examine all Heparin Sodium Injection vials to confirm the correct vial choice prior to administration of the drug.

Hypersensitivity

Patients with documented hypersensitivity to heparin should be given the drug only in clearly life-threatening situations (see ADVERSE REACTIONS , Hypersensitivity ).

Hemorrhage

Hemorrhage can occur at virtually any site in patients receiving heparin.  An unexplained fall in hematocrit, fall in blood pressure or any other unexplained symptom should lead to serious consideration of a hemorrhagic event.

Heparin sodium should be used with extreme caution in disease states in which there is increased danger of hemorrhage.  Some of the conditions in which increased danger of hemorrhage exists are:

Cardiovascular —Subacute bacterial endocarditis, severe hypertension.

Surgical —During and immediately following (a) spinal tap or spinal anesthesia or (b) major surgery, especially involving the brain, spinal cord, or eye.

Hematologic —Conditions associated with increased bleeding tendencies, such as hemophilia, thrombocytopenia and some vascular purpuras.

Gastrointestinal —Ulcerative lesions and continuous tube drainage of the stomach or small intestine.

Other —Menstruation, liver disease with impaired hemostasis .

Coagulation Testing

When heparin sodium is administered in therapeutic amounts, its dosage should be regulated by frequent blood coagulation tests.  If the coagulation test is unduly prolonged or if hemorrhage occurs, heparin sodium should be promptly discontinued (see OVERDOSAGE ).

Thrombocytopenia

Thrombocytopenia has been reported to occur in patients receiving heparin with a reported incidence of up to 30%.  Platelet counts should be obtained at baseline and periodically during heparin administration.  Mild thrombocytopenia (count greater than 100,000/mm3) may remain stable or reverse even if heparin is continued.  However, thrombocytopenia of any degree should be monitored closely.  If the count falls below 100,000/mm3 or if recurrent thrombosis develops (see Heparin-induced Thrombocytopenia and Heparin-induced Thrombocytopenia and Thrombosis ), the heparin product should be discontinued and, if necessary, an alternative anticoagulant administered .

Heparin-induced Thrombocytopenia (HIT) and Heparin-induced Thrombocytopenia and Thrombosis (HITT)

Heparin-induced Thrombocytopenia (HIT) is a serious antibody-mediated reaction resulting from irreversible aggregation of platelets.  HIT may progress to the development of venous and arterial thromboses, a condition referred to as Heparin-induced Thrombocytopenia and Thrombosis (HITT).  Thrombotic events may also be the initial presentation for HITT.  These serious thromboembolic events include deep vein thrombosis, pulmonary embolism, cerebral vein thrombosis, l imb ischemia, stroke, myocardial infarction, mesenteric thrombosis, renal arterial thrombosis, skin necrosis, gangrene of the extremities that may lead to amputation, and possibly death.  Thrombocytopenia of any degree should be monitored closely.  If the platelet count falls below 100,000/mm 3 or if recurrent thrombosis develops, the heparin product should be promptly discontinued and alternative anticoagulants considered, if patients require continued anticoagulation.

Delayed Onset of HIT and HITT

Heparin-induced Thrombocytopenia and Heparin-induced Thrombocytopenia and Thrombosis can occur up to several weeks after the discontinuation of heparin therapy.  Patients presenting with thrombocytopenia or thrombosis after discontinuation of heparin should be evaluated for HIT and HITT.

PRECAUTIONS

General

Thrombocytopenia, Heparin-induced Thrombocytopenia (HIT) and Heparin-induced Thrombocytopenia and Thrombosis (HITT)

See WARNINGS.

Heparin Resistance— Increased resistance to heparin is frequently encountered in fever, thrombosis, thrombophlebitis, infections with thrombosing tendencies, myocardial infarction, cancer and in postsurgical patients.

Increased Risk to Older Patients, Especially Women— A higher incidence of bleeding has been reported in patients, particularly women, over 60 years of age.

Laboratory Tests

Periodic platelet counts, hematocrits, and tests for occult blood in stool are recommended during the entire course of heparin therapy, regardless of the route of administration (see DOSAGE AND ADMINISTRATION ).

Drug Interactions

Oral Anticoagulants— Heparin sodium may prolong the one-stage prothrombin time.  Therefore, when heparin sodium is given with dicumarol or warfarin sodium, a period of at least five hours after the last intravenous dose or 24 hours after the last subcutaneous dose should elapse before blood is drawn, if a valid prothrombin time is to be obtained.

Platelet Inhibitors— Drugs such as acetylsalicylic acid, dextran, phenylbutazone, ibuprofen, indomethacin, dipyridamole, hydroxychloroquine and others that interfere with platelet-aggregation reactions (the main hemostatic defense of heparinized patients) may induce bleeding and should be used with caution in patients receiving heparin sodium.

Other Interactions— Digitalis, tetracyclines, nicotine or antihistamines may partially counteract the anticoagulant action of heparin sodium.  Intravenous nitroglycerin administered to heparinized patients may result in a decrease of the partial thromboplastin time with subsequent rebound effect upon discontinuation of nitroglycerin Careful monitoring of partial thromboplastin time and adjustment of heparin dosage are recommended during coadministration of heparin and intravenous nitroglycerin.

Drug/Laboratory Tests Interactions

Hyperaminotransferasemia —Significant elevations of aminotransferase (SGOT [S-AST] and SGPT [S-ALT]) levels have occurred in a high percentage of patients (and healthy subjects) who have received heparin.  Since aminotransferase determinations are important in the differential diagnosis of myocardial infarction, liver disease and pulmonary emboli, increases that might be caused by drugs (like heparin) should be interpreted with caution.

Carcinogenesis, Mutagenesis, Impairment of Fertility

No long-term studies in animals have been performed to evaluate carcinogenic potential of heparin. Also, no reproduction studies in animals have been performed concerning mutagenesis or impairment of fertility.

Pregnancy

Teratogenic Effects: Pregnancy Category C— Animal reproduction studies have not been conducted with heparin sodium.  It is also not known whether heparin sodium can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity.  Heparin sodium should be given to a pregnant woman only if clearly needed.

Nonteratogenic Effects —Heparin does not cross the placental barrier.

Nursing Mothers

Heparin is not excreted in human milk.

Pediatric Use

See DOSAGE AND ADMINISTRATION , Pediatric Use .

Geriatric Use

A higher incidence of bleeding has been reported in patients over 60 years of age, especially women (see PRECAUTIONS , General ).  Clinical studies indicate that lower doses of heparin may be indicated in these patients (see CLINICAL PHARMACOLOGY and DOSAGE AND ADMINISTRATION ).

Page last updated: 2014-07-10

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