Heparin Sodium Injection

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Description for Heparin Sodium Injection

Heparin is a heterogenous group of straight-chain anionic mucopolysaccharides, called glycosaminoglycans, possessing anticoagulant properties. It is composed of polymers of alternating derivations of α-D-glucosamido (N-sulfated O-sulfated or N-acetylated) and O-sulfated uronic acid (α-L-iduronic acid or β-D-glucuronic acid).

Structure of heparin sodium (representative subunits):

HEPARIN SODIUM INJECTION is a sterile preparation of heparin sodium derived from porcine intestinal tissue, standardized for anticoagulant activity, in water for injection. It is intended for intravenous or deep subcutaneous administration. The potency is determined by a biological assay using a USP reference standard based on units of heparin activity per milligram.

For formulations preserved with benzyl alcohol, each mL of the 1,000 and 5,000 USP units per mL preparations contains: heparin sodium 1,000 or 5,000 USP units; 9 mg sodium chloride; 9.45 mg benzyl alcohol added as preservative. Each mL of the 10,000 USP units per mL preparations contains: heparin sodium 10,000 USP units; 9.45 mg benzyl alcohol added as preservative.

The preservative-free product contains (per mL): 1,000 USP units of heparin sodium and 9 mg sodium chloride.

When necessary, the pH of HEPARIN SODIUM INJECTION is adjusted with hydrochloric acid and/or sodium hydroxide. The pH range is 5.0 to 7.5.

Uses for Heparin Sodium Injection

HEPARIN SODIUM INJECTION is indicated for:

• Prophylaxis and treatment of venous thrombosis and pulmonary embolism;
• Prophylaxis and treatment of thromboembolic complications associated with atrial fibrillation;
• Treatment of acute and chronic consumption coagulopathies (disseminated intravascular coagulation);
• Prevention of clotting in arterial and cardiac surgery;
• Prophylaxis and treatment of peripheral arterial embolism;
• Anticoagulant use in blood transfusions, extracorporeal circulation, and dialysis procedures.

Dosage for Heparin Sodium Injection

Preparation For Administration

Confirm the choice of the correct HEPARIN SODIUM INJECTION vial to ensure that the 1 mL vial is not confused with a ”catheter lock flush” vial or other 1 mL vial of incorrect strength [see WARNINGS AND PRECAUTIONS]. Confirm the selection of the correct formulation and strength prior to administration of the drug.

Inspect parenteral drug products visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Use only if solution is clear and the seal is intact. Do not use if solution is discolored or contains a precipitate.

When HEPARIN SODIUM INJECTION is added to an infusion solution for continuous intravenous (IV) administration, invert the container at least six times to ensure adequate mixing and prevent pooling of the heparin in the solution. Storage of prepared infusion solution should not exceed 4 hours at room temperature or 24 hours at 2 to 8°C. HEPARIN SODIUM INJECTION is incompatible with certain substances in solution (e.g., alteplase, amikacin sulfate, atracurium besylate, ciprofloxacin, cytarabine, daunorubicin, droperidol, erythromycin lactobionate, gentamicin sulfate, idarubicin, kanamycin sulfate, mitoxantrone HCl, polymyxin B sulfate, promethazine HCl, streptomycin sulfate, tobramycin sulfate). Consult specialized references to verify with which substances incompatibilities have been noted, as compatibility may depend on concentration, temperature, time, and other variables.

Administer HEPARIN SODIUM INJECTION by intermittent IV injection, IV infusion, or deep subcutaneous (intrafat, i.e., above the iliac crest or abdominal fat layer) injection. HEPARIN SODIUM INJECTION is not intended for intramuscular (IM) use [see ADVERSE REACTIONS].

Laboratory Monitoring For Efficacy And Safety

Adjust the dosage of HEPARIN SODIUM INJECTION according to the patient's coagulation test results. Dosage is considered adequate when the activated partial thromboplastin time (aPTT) is 1.5 to 2 times normal or when the whole blood clotting time is elevated approximately 2.5 to 3 times the control value. When initiating treatment with HEPARIN SODIUM INJECTION by continuous intravenous infusion, determine the coagulation status (aPTT, INR, platelet count) at baseline and continue to follow aPTT approximately every 4 hours and then at appropriate intervals thereafter. When the drug is administered intermittently by intravenous injection, perform coagulation tests before each injection during initiation of treatment and at appropriate intervals thereafter. After deep subcutaneous (SC) injections, tests for adequacy of dosage are best performed on samples drawn 4 to 6 hours after the injections.

Periodic platelet counts and hematocrits are recommended during the entire course of HEPARIN SODIUM INJECTION therapy, regardless of the route of administration.

Therapeutic Anticoagulant Effect With Full-Dose Heparin

The dosing recommendations in Table 1 are based on clinical experience. Although dosages must be adjusted for the individual patient according to the results of suitable laboratory tests, the following dosage schedules may be used as guidelines:

Table 1: Recommended Adult Full-Dose Heparin Regimens for Therapeutic Anticoagulant Effect

METHOD OF ADMINISTRATION	FREQUENCY	RECOMMENDED DOSE*
Deep Subcutaneous (Intrafat) Injection Use a different site for each injection to prevent the development of hematoma	Initial Dose	333 units/kg subcutaneously
	Every 12 hours	250 units/kg subcutaneously
Intermittent Intravenous Injection	Initial Dose	10,000 units, either undiluted or in 50 to 100 mL of 0.9% Sodium Chloride Injection, USP
	Every 4 to 6 hours	5,000 to 10,000 units, either undiluted or in 50 to 100 mL of 0.9% Sodium Chloride Injection, USP
Continuous Intravenous Infusion	Initial Dose	5.000    units by IV injection 20.000    to 40,000 units per 24 hours in 1,000 mL of 0.9% Sodium Chloride Injection, USP (or in any compatible solution) for infusion
	Continuous
* Based on 150 lb (68 kg) patient

Pediatric Use

Use preservative-free HEPARIN SODIUM INJECTION in neonates and infants.

There are no adequate and well controlled studies on heparin use in pediatric patients. Pediatric dosing recommendations are based on clinical experience. In general, the following dosage schedule may be used as a guideline in pediatric patients:

Initial Dose	75 to 100 units/kg (IV bolus over 10 minutes) Infants: 25 to 30 units/kg/hour;
Maintenance Dose	Infants < 2 months have the highest requirements (average 28 units/kg/hour) Children > 1 year of age: 18 to 20 units/kg/hour; Older children may require less heparin, similar to weight-adjusted adult dosage
Monitoring	Adjust heparin to maintain aPTT of 60 to 85 seconds, assuming this reflects an anti-Factor Xa level of 0.35 to 0.70.

Cardiovascular Surgery

Patients undergoing total body perfusion for open-heart surgery should receive an initial dose of not less than 150 units of heparin sodium per kilogram of body weight. Frequently, a dose of 300 units per kilogram is used for procedures estimated to last less than 60 minutes or 400 units per kilogram for those estimated to last longer than 60 minutes.

Low-Dos e Prophylaxis Of Postoperative Thromboembolism

The most widely used dosage has been 5,000 units 2 hours before surgery and 5,000 units every 8 to 12 hours thereafter for 7 days or until the patient is fully ambulatory, whichever is longer. Administer the heparin by deep subcutaneous (intrafat, i.e., above the iliac crest or abdominal fat layer, arm, or thigh) injection with a fine (25 to 26-gauge) needle to minimize tissue trauma.

Blood Transfusion

Addition of 400 to 600 USP units per 100 mL of whole blood is usually employed to prevent coagulation. Usually, 7,500 USP units of heparin sodium are added to 100 mL of 0.9% Sodium Chloride Injection, USP (or 75,000 USP units per 1,000 mL of 0.9% Sodium Chloride Injection, USP) and mixed; from this sterile solution, 6 to 8 mL are added per 100 mL of whole blood.

Converting To Warfarin

To ensure continuous anticoagulation when converting from HEPARIN SODIUM INJECTION to warfarin, continue full heparin therapy for several days until the INR (prothrombin time) has reached a stable therapeutic range. Heparin therapy may then be discontinued without tapering [see DRUG INTERACTIONS].

Converting To Dabigatran

For patients currently receiving intravenous heparin, stop intravenous infusion of heparin sodium immediately after administering the first dose of oral dabigatran (PRADAXA®); or for intermittent intravenous administration of heparin sodium, start oral dabigatran 0 to 2 hours before the time that the Based on 150 lb (68 kg) patient next dose of heparin was to have been administered.

Extracorporeal Dialysis

Follow equipment manufacturers' operating directions carefully. A dose of 25 to 30 units/kg followed by an infusion rate of 1,500 to 2,000 units/hour is suggested based on pharmacodynamic data if specific manufacturers' recommendations are not available.

HOW SUPPLIED

Dosage Forms And Strengths

HEPARIN SODIUM INJECTION is available as:

• 1,000 USP units/mL preservative-free
  Vial: 2,000 USP units/2 mL
• 1,000 USP units/mL preserved with benzyl alcohol
  Vial: 10,000 USP units/10 mL
  Vial: 30,000 USP units/30 mL
• 5,000 USP units/mL preserved with benzyl alcohol
  Vial: 50,000 USP units/10 mL
  Vial: 5,000 USP units/1 mL
• 10,000 USP units/mL preserved with benzyl alcohol
  Vial: 10,000 USP units/1 mL

Storage And Handling

HEPARIN SODIUM INJECTION pres ervative-free is available in the following strengths and package sizes:

DESCRIPTION	NDC
1,000 USP units/mL
Preservative-free, 1 vial: 2,000 USP units/2 mL, singledose*	0069-0043-02
Preservative-free, 25 vials: 2,000 USP units/2 mL, single-dose*	0069-0043-01
*Discard unused portion

HEPARIN SODIUM INJECTION preserved with benzyl alcohol is available in the following strengths and package sizes:

DESCRIPTION	NDC
1,000 USP units/mL
1 vial: 10,000 USP units/10 mL, multiple-dose	0069-0058-02
25 vials: 10,000 USP units/10 mL, multiple-dose	0069-0058-01
1 vial: 30,000 USP units/30 mL, multiple-dose	0069-0137-01
10 vials: 30,000 USP units/30 mL, multiple-dose	0069-0137-03
5,000 USP units/mL
1 vial: 50,000 USP units/10 mL, multiple-dose	0069-0059-02
25 vials: 50,000 USP units/10 mL, multiple-dose	0069-0059-01
1 vial: 5,000 USP units/1 mL, multiple-dose	0069-0059-04
25 vials: 5,000 USP units/1 mL, multiple-dose	0069-0059-03
10,000 USP units/mL
1 vial: 10,000 USP units/1 mL, multiple-dose	0069-0062-02
25 vials: 10,000 USP units/1 mL, multiple-dose	0069-0062-01

Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature]. Use only if solution is clear and the seal is intact. Do not use if solution is discolored or contains a precipitate.

Distributed by: Pfizer Labs Division of Pfizer Inc., New York, NY, NY 10017. Revised: Mar 2013

Side Effects for Heparin Sodium Injection

Hemorrhage

Hemorrhage is the chief complication that may result from heparin therapy (see WARNINGS). An overly prolonged clotting time or minor bleeding during therapy can usually be controlled by withdrawing the drug (see OVERDOSE). It should be appreciated that gastrointestinal or urinary tract bleeding during anticoagulant therapy may indicate the presence of an underlying occult lesion. Bleeding can occur at any site but certain specific hemorrhagic complications may be difficult to detect:

1. Adrenal hemorrhage, with resultant acute adrenal insufficiency, has occurred during anticoagulant therapy. Therefore, such treatment should be discontinued in patients who develop signs and symptoms of acute adrenal hemorrhage and insufficiency. Initiation of corrective therapy should not depend on laboratory confirmation of the diagnosis, since any delay in an acute situation may result in the patient’s death.
2. Ovarian (corpus luteum) hemorrhage developed in a number of women of reproductive age receiving short- or long-term anticoagulant therapy. This complication, if unrecognized, may be fatal.
3. Retroperitoneal hemorrhage.

Thrombocytopenia, Heparin-induced Thrombocytopenia (HIT) (With or Without Thrombosis) and Delayed Onset of HIT (With or Without Thrombosis).

See WARNINGS.

Local Irritation

Local irritation, erythema, mild pain, hematoma or ulceration may follow deep subcutaneous (intrafat) injection of heparin sodium. These complications are much more common after intramuscular use, and such use is not recommended.

Hypersensitivity

Generalized hypersensitivity reactions have been reported, with chills, fever and urticaria as the most usual manifestations, and asthma, rhinitis, lacrimation, headache, nausea and vomiting, and anaphylactoid reactions, including shock, occurring more rarely. Itching and burning, especially on the plantar side of the feet, may occur (see WARNINGS and PRECAUTIONS).

Certain episodes of painful, ischemic and cyanosed limbs have in the past been attributed to allergic vasospastic reactions. Whether these are in fact identical to the thrombocytopenia associated complications remains to be determined.

Hyperkalemia

Heparin can suppress adrenal secretion of aldosterone leading to hyperkalemia, particularly in patients with diabetes mellitus, chronic renal failure, pre-existing metabolic acidosis, a raised plasma potassium, or taking potassium sparing drugs. The risk of hyperkalemia appears to increase with duration of therapy but is usually reversible upon discontinuation of heparin.

Measure blood potassium in patients at risk of hyperkalemia before starting heparin therapy and periodically in all patients treated for more than 5 days or earlier as deemed fit by the clinician.

Miscellaneous

Osteoporosis following long-term administration of high doses of heparin, cutaneous necrosis after systemic administration, suppression of aldosterone synthesis, delayed transient alopecia, priapism, and rebound hyperlipemia on discontinuation of heparin sodium have also been reported.

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.

Metabolism And Nutrition Disorders

Hyperkalemia

Drug Interactions for Heparin Sodium Injection

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 5 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 Test 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.

Warnings for Heparin Sodium Injection

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 sterile cartridge needle units. 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 syringes to confirm the correct product choice prior to administration of the drug.

Benzyl Alcohol Toxicity

Use preservative-free Heparin Sodium Injection, USP in neonates and infants. The preservative benzyl alcohol has been associated with serious adverse events and death in pediatric patients. The minimum amount of benzyl alcohol at which toxicity may occur is not known. Premature and low-birth weight infants may be more likely to develop toxicity (see PRECAUTIONS, Pediatric Use).

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 OVERDOSE).

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 (HIT) (With Or Without Thrombosis)), the heparin product should be discontinued and, if necessary, an alternative anticoagulant administered.

Heparin-Induced Thrombocytopenia (HIT) (With Or Without Thrombosis)

HIT is a serious immune-mediated reaction resulting from irreversible aggregation of platelets. HIT may progress to the development of venous and arterial thromboses, a condition referred to as HIT with thrombosis. Thrombotic events may also be the initial presentation for HIT. 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 fatal outcomes.

Once HIT (with or without thrombosis) is diagnosed or strongly suspected, all heparin sodium sources (including heparin flushes) should be discontinued and an alternative anticoagulant used. Future use of heparin sodium, especially within 3 to 6 months following the diagnosis of HIT (with or without thrombosis), and while patients test positive for HIT antibodies, should be avoided.

Immune-mediated HIT is diagnosed based on clinical findings supplemented by laboratory tests confirming the presence of antibodies to heparin sodium, or platelet activation induced by heparin sodium. A drop in platelet count greater than 50% from baseline is considered indicative of HIT. Platelet counts begin to fall 5 to 10 days after exposure to heparin sodium in heparin sodium-naïve individuals, and reach a threshold by days 7 to 14. In contrast, “rapid onset” HIT can occur very quickly (within 24 hours following heparin sodium initiation), especially in patients with a recent exposure to heparin sodium (i.e. previous 3 months). Thrombosis development shortly after documenting thrombocytopenia is a characteristic finding in almost half of all patients with HIT.

Thrombocytopenia of any degree should be monitored closely. If the platelet count falls below 100,000/mm³ 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 (With Or Without Thrombosis)

Heparin-induced Thrombocytopenia (with or without thrombosis) 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 (with or without thrombosis).

Use In Neonates

Heparin Sodium Injection contains the preservative benzyl alcohol as a preservative and is not recommended for use in neonates. There have been reports of fatal “gasping syndrome” in neonates (children less than one month of age) following the administration of intravenous solutions containing the preservative benzyl alcohol. Symptoms include a striking onset of gasping respiration, hypotension, bradycardia, and cardiovascular collapse.

Carefully examine all Heparin Sodium Injection vials and syringes to confirm choice of the correct strength prior to administration of the drug. Pediatric patients, including neonates, have died as a result of medication errors in which Heparin Sodium Injection vials have been confused with “catheter lock flush” vials. (See WARNINGS, Fatal Medication Errors.)

Precautions for Heparin Sodium Injection

General

Thrombocytopenia, Heparin-induced Thrombocytopenia (HIT) (With or Without Thrombosis) and Delayed Onset of HIT (With or Without Thrombosis)

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).

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

There are no adequate and well-controlled studies on heparin use in pregnant women. In published reports, heparin exposure during pregnancy did not show evidence of an increased risk of adverse maternal or fetal outcomes in humans. Heparin sodium does not cross the placenta based on human and animal studies. Administration of heparin to pregnant animals at doses higher than the maximum human daily dose based on body weight resulted in increased resorptions. Use heparin sodium during pregnancy only if the potential benefit justifies the potential risk to the fetus.

If available, preservative-free Heparin Sodium Injection is recommended when heparin therapy is needed during pregnancy. There are no known adverse outcomes associated with fetal exposure to the preservative benzyl alcohol through maternal drug administration; however, the preservative benzyl alcohol can cause serious adverse events and death when administered intravenously to neonates and infants (see PRECAUTIONS, Pediatric Use).

In a published study conducted in rats and rabbits, pregnant animals received heparin intravenously during organogenesis at a dose of 10,000 units/kg/day, approximately 10 times the maximum human daily dose based on body weight. The number of early resorptions increased in both species. There was no evidence of teratogenic effects.

Nursing Mothers

If available, preservative-free Heparin Sodium Injection is recommended when heparin therapy is needed during lactation. Due to its large molecular weight, heparin is not likely to be excreted in human milk, and any heparin in milk would not be orally absorbed by a nursing infant. Benzyl alcohol present in maternal serum is likely to cross into human milk and may be orally absorbed by a nursing infant. Exercise caution when administering Heparin Sodium Injection, USP to a nursing mother (see PRECAUTIONS, Pediatric Use).

Pediatric Use

There are no adequate and well controlled studies on heparin use in pediatric patients. Pediatric dosing recommendations are based on clinical experience (see DOSAGE AND ADMINISTRATION, Pediatric Use).

Carefully examine all Heparin Sodium Injection vials to confirm choice of the correct strength prior to administration of the drug. Pediatric patients, including neonates, have died as a result of medication errors in which Heparin Sodium Injection, USP vials have been confused with “catheter lock flush” vials (see WARNINGS, Fatal Medication Errors).

Benzyl Alcohol Toxicity

Use preservative-free Heparin Sodium Injection in neonates and infants. The preservative benzyl alcohol has been associated with serious adverse events and death in pediatric patients. The “gasping syndrome” (characterized by central nervous system depression, metabolic acidosis, gasping respirations, and high levels of benzyl alcohol and its metabolites found in the blood and urine) has been associated with benzyl alcohol dosages >99 mg/kg/day in neonates and low-birth weight infants. Additional symptoms may include gradual neurological deterioration, seizures, intracranial hemorrhage, hematologic abnormalities, skin breakdown, hepatic and renal failure, hypotension, bradycardia, and cardiovascular collapse.

Although normal therapeutic doses of this product deliver amounts of benzyl alcohol that are substantially lower than those reported in association with the “gasping syndrome”, the minimum amount of benzyl alcohol at which toxicity may occur is not known. Premature and low-birth weight infants may be more likely to develop toxicity. Practitioners administering this and other medications containing benzyl alcohol should consider the combined daily metabolic load of benzyl alcohol from all sources.

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).

Overdose Information for Heparin Sodium Injection

Symptoms

Bleeding is the chief sign of heparin overdosage. Nosebleeds, blood in urine or tarry stools may be noted as the first sign of bleeding. Easy bruising or petechial formations may precede frank bleeding.

Treatment – Neutralization Of Heparin Effect

When clinical circumstances (bleeding) require reversal of heparinization, protamine sulfate (1% solution) by slow infusion will neutralize heparin sodium. No more than 50 mg should be administered, very slowly, in any 10-minute period. Each mg of protamine sulfate neutralizes approximately 100 USP heparin Units. The amount of protamine required decreases over time as heparin is metabolized. Although the metabolism of heparin is complex, it may, for the purpose of choosing a protamine dose, be assumed to have a half-life of about 1/2 hour after intravenous injection.

Administration of protamine sulfate can cause severe hypotensive and anaphylactoid reactions. Because fatal reactions often resembling anaphylaxis have been reported, the drug should be given only when resuscitation techniques and treatment of anaphylactoid shock are readily available.

For additional information consult the labeling of Protamine Sulfate Injection, USP products.

Contraindications for Heparin Sodium Injection

Heparin sodium should NOT be used in patients with the following conditions:

• Severe thrombocytopenia;
• When suitable blood coagulation tests, e.g., the whole blood clotting time, partial thromboplastin time, etc., cannot be performed at appropriate intervals (this contraindication refers to full-dose heparin; there is usually no need to monitor coagulation parameters in patients receiving low-dose heparin);
• An uncontrolled active bleeding state (see WARNINGS), except when this is due to disseminated intravascular coagulation.

Clinical Pharmacology for Heparin Sodium Injection

Heparin inhibits reactions that lead to the clotting of blood and the formation of fibrin clots both in vitro and in vivo. Heparin acts at multiple sites in the normal coagulation system. Small amounts of heparin in combination with antithrombin III (heparin cofactor) can inhibit thrombosis by inactivating activated Factor X and inhibiting the conversion of prothrombin to thrombin. Once active thrombosis has developed, larger amounts of heparin can inhibit further coagulation by inactivating thrombin and preventing the conversion of fibrinogen to fibrin. Heparin also prevents the formation of a stable fibrin clot by inhibiting the activation of the fibrin stabilizing factor.

Bleeding time is usually unaffected by heparin. Clotting time is prolonged by full therapeutic doses of heparin; in most cases, it is not measurably affected by low doses of heparin.

Patients over 60 years of age, following similar doses of heparin, may have higher plasma levels of heparin and longer activated partial thromboplastin times (APTTs) compared with patients under 60 years of age.

Peak plasma levels of heparin are achieved 2 to 4 hours following subcutaneous administration, although there are considerable individual variations. Log linear plots of heparin plasma concentrations with time, for a wide range of dose levels, are linear, which suggest the absence of zero order processes. Liver and the reticulo-endothelial system are the sites of biotransformation. The biphasic elimination curve, a rapidly declining alpha phase (t_1/2 = 10 min.), and after the age of 40 a slower beta phase, indicates uptake in organs. The absence of a relationship between anticoagulant half-life and concentration half-life may reflect factors such as protein binding of heparin.

Heparin does not have fibrinolytic activity; therefore, it will not lyse existing clots.

Patient Information for Heparin Sodium Injection

No information provided. Please refer to the WARNINGS AND PRECAUTIONS section.