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- By IV injection: acts immediately for about 2 to 4 hours
- SC injection: acts within 1 hour for about 8 to 12 hours
- Venous and arterial thrombosis: pulmonary embolism, myocardial infarction, thrombophlebitis
- Prevention of venous and arterial thrombosis, especially in pre-operative and postoperative period and in patients on bedrest
Prescription of heparin requires systematic monitoring of coagulation parameters.
Forms and strengths, route of administration
- 1000 IU in 1 ml ampoule (1000 IU/ml) and 5000 IU in 1 ml ampoule (5000 IU/ml) for IV injection or infusion, diluted in an isotonic solution of glucose or sodium chloride
- 25 000 IU in 1 ml ampoule (25 000 IU/ml) for SC injection
- Also comes in various concentrations (500 IU, 12 500 IU, 20 000 IU/ml) and volumes (0.5 ml, 2 ml, 5 ml). Check label before use.
- By IV route
Child and adult: initial dose of 50 to 100 IU/kg followed by 400 to 600 IU/kg daily, by continuous infusion over 24 hours or by IV injection every 2 to 4 hours. Adjust dosage according to coagulation tests.
- By SC route
Child and adult: 1 SC injection every 12 hours. Start with an initial dose of 250 IU/kg and adjust dosage according to coagulation tests.
- Usually: 5000 IU by SC injection 2 hours before surgery, repeated every 8 to 12 hours.
- Dosage depends on patient's weight and risk of thrombo-embolic complications: 75 IU/kg 2 times daily or 50 UI/kg 3 times daily.
- About 7 to 10 days or more according to clinical response.
- In postoperative period, administer until fully ambulatory.
- For long-term therapy, administer heparin simultaneously with oral anticoagulants for 2 to 3 days before stopping heparin.
Contra-indications, adverse effects, precautions
- Do not administer if:
- haemorrhage or risk of haemorrhage: haemophilia, active peptic ulcer, acute bacterial endocarditis, severe hypertension; in postoperative period after neurosurgery or ophtalmic surgery;
- thrombocytopenia or history of heparin-induced thrombocytopenia.
- Do not administer by IM route. SC injections must be made deep into abdominal fat, between umbilicus and iliac crest.
- Intramuscular or intra-arterial injections and infiltrations are contra-indicated during heparin therapy.
- May cause:
- severe thrombocytopenia, usually after 5 days of heparin, with thrombo-embolic complications requiring discontinuation of treatment;
- localised reactions at the injection site, rarely, necrosis;
- allergic reactions, osteoporosis after prolonged use, alopecia;
- haemorrhage in case of overdosage, pre-existing lesions, trauma.
- Use with caution and reduce dosage in elderly patients and in hepatic or renal failure.
- Overdosage: neutralise heparin by slow IV injection of protamine. 1 mg protamine neutralises 100 IU of heparin.
- Reduce doses of protamine if more than 15 minutes has elapsed since heparin administration.
- Laboratory tests:
- Monitor coagulation parameters in order to adjust dose. Partial thromboplastin time should be maintained at 1.5 to 2 times the control value (Howell's test at 2 to 3 times the control value).
- Monitor platelet count prior to initiation of treatment and then 2 times per week.
- Avoid combination with aspirin, non-steroidal anti-inflammatory drugs: increased risk of haemorrhage.
- Closely monitor clinical and biological parameters in case of combination with corticosteroids, dextran, and transition to an oral anticoagulant.
- Pregnancy: CONTRA-INDICATED at the end of pregnancy (risk of haemorrhage during delivery)
- Breast-feeding: no contra-indication
- Preparations containing calcium salt of heparin are available. Heparin sodium is usually used by IV route. Both sodium and calcium heparin are used by SC route. There is a little difference in the action of these 2 medications.
- Do not mix with other drugs in the same syringe.
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