HEPARIN SODIUM

(hep'a-rin)

Hepalean

, Heparin Sodium Lock Flush Solution, Hep-Lock
Classifications: anticoagulant;
Therapeutic: anticoagulant
Pregnancy Category: C

Availability

10 units/mL, 100 units/mL, 1000 units/mL 2000 units/mL, 5000 units/mL, 10,000 units/mL, 20,000 units/mL, 40,000 units/mL injection

Action

Exerts direct effect on the cascade of blood coagulation (clotting) by enhancing the inhibitory actions of antithrombin III (heparin cofactor) on several factors essential to normal blood clotting, thereby blocking the conversion of prothrombin to thrombin and fibrinogen to fibrin.

Therapeutic Effect

Inhibits formation of new clots. High molecular weight mucopolysaccharide with rapid anticoagulant effect. Does not lyse already existing thrombi but may prevent their extension and propagation.

Uses

Prophylaxis and treatment of venous thrombosis and pulmonary embolism and to prevent thromboembolic complications arising from cardiac and vascular surgery, frostbite, and during acute stage of MI. Also used in treatment of disseminated intravascular coagulation (DIC), atrial fibrillation with embolization, and as anticoagulant in blood transfusions, extracorporeal circulation, and dialysis procedures.

Unlabeled Uses

Prophylaxis in hip and knee surgery. Heparin Sodium Lock Flush Solution is used to maintain potency of indwelling IV catheters in intermittent IV therapy or blood sampling. It is not intended for anticoagulant therapy.

Contraindications

History of hypersensitivity to heparin (white clot syndrome); active bleeding, bleeding tendencies (hemophilia, purpura, thrombocytopenia); jaundice; ascorbic acid deficiency; inaccessible ulcerative lesions; visceral carcinoma; open wounds, extensive denudation of skin, suppurative thrombophlebitis; advanced kidney, liver, or biliary disease; active tuberculosis; bacterial endocarditis; continuous tube drainage of stomach or small intestines; threatened abortion; suspected intracranial hemorrhage, severe hypertension; recent surgery of eye, brain, or spinal cord; spinal tap; shock; pregnancy (category C), especially the last trimester.

Cautious Use

Alcoholism; history of allergy (asthma, hives, hay fever, eczema); during menstruation; immediate postpartum period; patients with indwelling catheters; older adults; use of acid-citrate-dextrose (ACD)-converted blood (may contain heparin); patients in hazardous occupations; cerebral embolism.

Route & Dosage

Treatment of Thromboembolism
Adult: IV 5000-unit bolus dose, then 20,000–40,000 units infused over 24 h, dose adjusted to maintain desired APTT or 5000–10,000 unit IV piggyback q4–6h SC 10,000–20,000 unit followed by 8000–20,000 units q8–12h
Child: IV 50 unit/kg bolus, then 20,000 unit/m²/24 h or 50–100 unit/kg q4h

Open Heart Surgery
Adult: IV 150–400 units/kg

Prophylaxis of Embolism
Adult: SC 5000 units q8–12h until patient is ambulatory

Administration

Note: Before administration, check coagulation test values; if results are not within therapeutic range, notify physician for dosage adjustment. Do not use solutions of heparin or heparin lock-flush that contain benzyl alcohol preservative in neonates.

Subcutaneous

Use more concentrated heparin solutions for SC injection.
Make injections into the fatty layer of the abdomen or just above the iliac crest. Avoid injecting within 5 cm (2 in.) of umbilicus or in a bruised area. Insert needle into tissue roll perpendicular to skin surface. Do not withdraw plunger to check entry into blood vessel. Systematically rotate injection sites and keep record.
Exercise caution to avoid IM injection.

Intravenous

PREPARE: Direct: Give undiluted. Intermittent/Continuous: ??May add to any amount of NS, D5W, or Ringer's for injection. ??Invert IV solution container at least 6 times to ensure adequate mixing.

ADMINISTER: Direct: Give a single dose over 60 sec. Intermittent/Continuous: Use infusion pump and give over 4–24 h.

INCOMPATIBILITIES Solution/additive: Alteplase, amikacin, atracurium, ciprofloxacin, codeine, cytarabine, dobutamine, doxorubicin, erythromycin, gentamicin, haloperidol, hyaluronidase, hydrocortisone, kanamycin, levorphanol, meperidine, methicillin, morphine, netilmicin, polymyxin B, promethazine, streptomycin, tetracycline, tobramycin, vancomycin. Y-site: Alteplase, amiodarone, amphotericin B cholesteryl, amsacrine, ciprofloxacin, clarithromycin, dacarbazine, diazepam, dobutamine, doxorubicin, doxycycline, droperidol, ergotamine, filgrastim, gatifloxacin, gentamicin, haloperidol, idarubicin, isosorbide, levofloxacin, methotrimeprazine, mexiletine, nitroglycerin, phenytoin, polymyxin B, tobramycin, tramadol, triflupromazine, vancomycin, vinorelbine.

Store at 15°–30° C (59°–86° F). Protect from freezing.

Adverse Effects (≥1%)

Hematologic: Spontaneous bleeding, transient thrombocytopenia, hypofibrinogenemia, "white clot syndrome." Body as a Whole: Fever, chills, urticaria, pruritus, skin rashes, itching and burning sensations of feet, numbness and tingling of hands and feet, elevated BP, headache, nasal congestion, lacrimation, conjunctivitis, chest pains, arthralgia, bronchospasm, anaphylactoid reactions. Endocrine: Osteoporosis, hypoaldosteronism, suppressed renal function, hyperkalemia; rebound hyperlipidemia (following termination of heparin therapy). GI: Increased AST, ALT. Urogenital: Priapism (rare). Skin: Injection site reactions: pain, itching, ecchymoses, tissue irritation and sloughing; cyanosis and pains in arms or legs (vasospasm), reversible transient alopecia (usually around temporal area).

Diagnostic Test Interference

Notify laboratory that patient is receiving heparin, when a test is to be performed. Possibility of false-positive rise in BSP test and in serum thyroxine; and increases in resin T₃ uptake; false-negative ¹²⁵I fibrinogen uptake. Heparin prolongs PT. Valid readings may be obtained by drawing blood samples at least 4–6 h after an IV dose (but at any time during heparin infusion) and 12–24 h after an SC heparin dose.

Interactions

Drug: May prolong PT, which is used to monitor therapy with oral anticoagulants; aspirin, nsaids increase risk of bleeding; nitroglycerin IV may decrease anticoagulant activity; protamine antagonizes effects of heparin. Herbal: Feverfew, ginkgo, ginger may potentiate bleeding.

Pharmacokinetics

Onset: 20–60 min SC. Peak: Within minutes. Duration: 2–6 h IV; 8–12 h SC. Distribution: Does not cross placenta; not distributed into breast milk. Metabolism: In liver and by reticuloendothelial system. Elimination: In urine. Half-Life: 90 min.

Nursing Implications

Assessment & Drug Effects

Lab tests: Baseline blood coagulation tests, Hct, Hgb, RBC, and platelet counts prior to initiation of therapy and at regular intervals throughout therapy.
Monitor APTT levels closely.
Note: In general, dosage is adjusted to keep APTT between 1.5–2.5 times normal control level.
Draw blood for coagulation test 30 min before each scheduled SC or intermittent IV dose and approximately q4h for patients receiving continuous IV heparin during dosage adjustment period. After dosage is established, tests may be done once daily.
Patients vary widely in their reaction to heparin; risk of hemorrhage appears greatest in women, all patients >60 y, and patients with liver disease or renal insufficiency.
Monitor vital signs. Report fever, drop in BP, rapid pulse, and other S&S of hemorrhage.
Observe all needle sites daily for hematoma and signs of inflammation (swelling, heat, redness, pain).
Antidote: Have on hand protamine sulfate (1% solution), specific heparin antagonist.

Patient & Family Education

Protect from injury and notify physician of pink, red, dark brown, or cloudy urine; red or dark brown vomitus; red or black stools; bleeding gums or oral mucosa; ecchymoses, hematoma, epistaxis, bloody sputum; chest pain; abdominal or lumbar pain or swelling; unusual increase in menstrual flow; pelvic pain; severe or continuous headache, faintness, or dizziness.
Note: Menstruation may be somewhat increased and prolonged; usually, this is not a contraindication to continued therapy if bleeding is not excessive.
Learn correct technique for SC administration if discharged from hospital on heparin.
Engage in normal activities such as shaving with a safety razor in the absence of a low platelet (thrombocyte) count. Usually, heparin does not affect bleeding time.
Caution: Smoking and alcohol consumption may alter response to heparin and are not advised.
Do not take aspirin or any other OTC medication without physician's approval.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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