heparin sodium

Action

Inhibits thrombus by preventing conversion of prothrombin to thrombin and fibrinogen to fibrin, preventing clot formation. Doesn't lyse existing clot, but prevents clot enlargement and extension.

Availability

Solution for flushes: 1-unit/ml, 2-units/ml, 10-units/ml, 100-units/ml syringes; 100-units/ml vials

Solution for injection: 1,000 units/ml, 10,000 units/ml, 20,000 units/ml, 40,000 units/ml in single-dose vials; 1,000 units/ml, 2,000 units/ml, 5,000 units/ml, 10,000 units/ml, 20,000 units/ml in multidose vials; 1,000 units/ml, 2,500 units/ml, 5,000 units/ml, 10,000 units/ml in unit-dose syringes

Indications and dosages

➣ Therapeutic anticoagulation

Adults: 10,000 units I.V. by intermittent bolus, then 5,000 to 10,000 units I.V. q 4 to 6 hours. Or 5,000 units by I.V. injection, then 20,000 to 40,000 units I.V. over 24 hours (about 1,000 units/hour or 15 to 18 units/kg/hour). Or 5,000 units I.V., followed by initial deep subcutaneous dose of 10,000 to 20,000 units, then 8,000 to 10,000 units q 8 hours or 15,000 to 20,000 units q 12 hours.

Children: Initially, 50 units/kg by I.V. drip, then 100 units/kg by I.V. drip q 4 hours. Or 20,000 units/m²/24 hours by continuous I.V. infusion.

➣ To prevent thromboembolism

Adults: 5,000 units subcutaneously q 8 to 12 hours (may begin 2 hours before surgery) given for 7 days or until patient is fully ambulatory

➣ To prevent blood clotting during cardiovascular surgery

Adults: At least 150 units/kg I.V. (300 units/kg if procedure less than 60 minutes; 400 units/kg if more than 60 minutes)

➣ I.V. flush

Adults and children: 10 to 100 units/ml I.V. heparin sodium solution to fill heparin lock set

Off-label uses

• Prophylaxis of left ventricular thrombi

• Prophylaxis of cerebrovascular accident after myocardial infarction

Contraindications

• Hypersensitivity to drug

• Bleeding disorders

• Severe thrombocytopenia

• Patients who can't undergo regular blood coagulation tests

Precautions

Use cautiously in:

• severe hepatic or renal disease, bacterial endocarditis, hypertension, brain injury, retinopathy, ulcer disease

• recent CNS or ophthalmic surgery

• immediate postpartum period

• women older than age 60

• pregnant patients.

Administration

See Know that I.V. heparin sodium is a high-alert drug.

• Draw baseline blood sample for clotting studies before starting drug.

See Use infusion pump to administer I.V. dose. Check regularly to ensure that infusion rate is correct.

• For I.V. use, give each 1,000-unit dose or single-dose injection over at least 1 minute. Give continuous infusion over 4 to 24 hours, depending on dose and volume of infusion solution.

• Draw blood for partial thromboplastin time (PTT) from opposite arm 4 hours after continuous I.V. infusion begins.

• Put note at patient's bedside to remind personnel to apply pressure dressings after withdrawing blood.

• With intermittent I.V. drug infusion, withdraw blood 30 minutes before dose, using arm without I.V. infusion.

• For subcutaneous dose, inject slowly between iliac crests in lower abdomen, deep into subcutaneous fat layer. Leave needle in place for 10 seconds before withdrawing. Don't massage area after injection. Alternate subcutaneous sites every 12 hours.

• Have protamine available as heparin agonist.

See Don't give I.M.

See Don't give heparin products containing benzyl alcohol to premature infants.

Adverse reactions

EENT: rhinitis

Hematologic: anemia, thrombocytopenia, bleeding, severely prolonged clotting time

Hepatic: hepatitis

Metabolic: hyperkalemia

Musculoskeletal: osteoporosis (with long-term use)

Skin: irritation, rash, urticaria, hematoma, ulceration, cutaneous or subcutaneous necrosis, pruritus, alopecia (with long-term use)

Other: fever, pain at injection site, hypersensitivity reactions, white clot syndrome, anaphylactoid reactions

Interactions

Drug-drug. Antihistamines, digoxin, nicotine, tetracyclines: decreased anticoagulant effect of heparin

Cefamandole, cefmetazole, cefoperazone, cefotetan, plicamycin, quinidine, valproic acid, other drugs that cause hypoprothrombinemia; drugs that affect platelet function (including abciximab, aspirin, clopidogrel, dextran, dipyridamole, eptifibitide, nonsteroidal anti-inflammatory drugs, some penicillins, thrombolytics, ticlopidine, tirofiban): increased bleeding risk

Drug-diagnostic tests. Alanine aminotransferase, aspartate aminotransferase, free fatty acids, thyroxine, triiodothyronine resin: increased levels

Cholesterol, triglycerides: decreased levels

¹²⁵I fibrinogen uptake: false-negative result

Prothrombin time: prolonged

Drug-herbs. Anise, arnica, chamomile, clove, dong quai, feverfew, garlic, ginger, ginseng: increased bleeding risk

Drug-behaviors. Smoking: increased bleeding risk

Patient monitoring

• Monitor infusion rate closely, even when using infusion pump.

• Evaluate patient's vital signs.

See Watch for signs and symptoms of anaphylactoid reaction.

See Assess for white clot syndrome (new thrombus formation in association with thrombocytopenia caused by irreversible platelet aggregation).

See Stay alert for signs and symptoms of bleeding tendency.

• Check hematocrit, PTT, and platelet count frequently.

• Monitor liver function test results.

• In long-term therapy, periodically assess stool for occult blood.

• Monitor potassium level in patients with diabetes or renal disease. (Drug may cause hyperkalemia.)

Patient teaching

• If patient will self-administer drug, teach proper technique and emphasize need to rotate injection sites.

See Advise patient that nosebleed, blood in urine, or black stools may be first sign of overdose and should be reported immediately.

See Tell patient to immediately report other unusual bleeding or bruising.

• Urge patient to avoid activities that can cause injury. Advise him to use soft toothbrush and electric razor to avoid gum and skin injury.

• Tell patient he will undergo regular blood testing during therapy.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above.