5 WARNINGS AND PRECAUTIONS
5.1 Fatal Medication Errors
Do not use Heparin Sodium Injection as a "catheter lock flush" product. Heparin Sodium Injection is supplied in vials and sterile cartridges 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 and cartridges to confirm the correct product choice prior to administration of the drug.
Avoid using heparin in the presence of major bleeding, except when the benefits of heparin therapy outweigh the potential risks.
Hemorrhage can occur at virtually any site in patients receiving heparin. Fatal hemorrhages have occurred. Adrenal hemorrhage (with resultant acute adrenal insufficiency), ovarian hemorrhage, and retroperitoneal hemorrhage have occurred during anticoagulant therapy with heparin [see Adverse Reactions (6.2)]. A higher incidence of bleeding has been reported in patients, particularly women, over 60 years of age [see Clinical Pharmacology (12.3)]. An unexplained fall in hematocrit, fall in blood pressure or any other unexplained symptom should lead to serious consideration of a hemorrhagic event.
Use Heparin Sodium with caution in disease states in which there is increased risk of hemorrhage, including:
- 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.
- Patients with hereditary antithrombin III deficiency receiving concurrent antithrombin III therapy — The anticoagulant effect of heparin is enhanced by concurrent treatment with antithrombin III (human) in patients with hereditary antithrombin III deficiency. To reduce the risk of bleeding, reduce the heparin dose during concomitant treatment with antithrombin III (human).
- Gastrointestinal — Ulcerative lesions and continuous tube drainage of the stomach or small intestine.
- Other — Menstruation, liver disease with impaired hemostasis.
5.3 Heparin-induced Thrombocytopenia and Heparin-Induced Thrombocytopenia and Thrombosis
Heparin-Induced Thrombocytopenia (HIT) is a serious antibody-mediated reaction. HIT occurs in patients treated with heparin and is due to the development of antibodies to a platelet Factor 4-heparin complex that induce in vivo platelet aggregation. HIT may progress to the development of venous and arterial thromboses, a condition referred to as heparin-induced thrombocytopenia with 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, limb ischemia, stroke, myocardial infarction, mesenteric thrombosis, renal arterial thrombosis, skin necrosis, gangrene of the extremities that may lead to amputation, and possibly death. If the platelet count falls below 100,000/mm3 or if recurrent thrombosis develops, promptly discontinue heparin, evaluate for HIT and HITT, and, if necessary, administer an alternative anticoagulant.
HIT or HITT can occur up to several weeks after the discontinuation of heparin therapy. Patients presenting with thrombocytopenia or thrombosis after discontinuation of Heparin Sodium should be evaluated for HIT or HITT.
5.4 Risk of Serious Adverse Reactions in Infants Due to Benzyl Alcohol Preservative
Serious and fatal adverse reactions including "gasping syndrome" can occur in neonates and infants treated with benzyl alcohol-preserved drugs, including Heparin Sodium Injection multiple-dose vials. The "gasping syndrome" is characterized by central nervous system depression, metabolic acidosis, and gasping respirations.
The minimum amount of benzyl alcohol at which toxicity may occur is not known[see Use in Specific Populations(8.4)].
Thrombocytopenia in patients receiving heparin has been reported at frequencies up to 30%. It can occur 2 to 20 days (average 5 to 9) following the onset of heparin therapy. Obtain platelet counts before and periodically during heparin therapy. Monitor thrombocytopenia of any degree closely. If the count falls below 100,000/mm3 or if recurrent thrombosis develops, promptly discontinue heparin, evaluate for HIT and HITT, and, if necessary, administer an alternative anticoagulant [see Warnings and Precautions (5.3)].
5.6 Coagulation Testing and Monitoring
When using a full dose heparin regimen, adjust the heparin dose based on frequent blood coagulation tests. If the coagulation test is unduly prolonged or if hemorrhage occurs, discontinue heparin promptly [see Overdosage (10)]. Periodic platelet counts and hematocrits are recommended during the entire course of heparin therapy, regardless of the route of administration [see Dosage and Administration (2.2)].
5.7 Heparin Resistance
Resistance to heparin is frequently encountered in fever, thrombosis, thrombophlebitis, infections with thrombosing tendencies, myocardial infarction, cancer, in postsurgical patients, and patients with antithrombin III deficiency. Close monitoring of coagulation tests is recommended in these cases. Adjustment of heparin doses based on anti-Factor Xa levels may be warranted.