HEPARIN injectable

• Anticoagulant
  • By IV injection: acts immediately for about 2 to 4 hours
  • SC injection: acts within 1 hour for about 8 to 12 hours

Indications

• 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.

Dosage

Curative treatment

• 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.

Preventive treatment

• 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.

Duration

• 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

Remarks

• 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.

Storage