Composition: Reviparin sodium, 0.25ml of solution contains 1,432 units of anti-Factor Xa activity.
Presentation: Solution for subcutaneous injection.
Action: Low molecular weight heparin. Anticoagulant.
Indications: Prevention of thrombosis and thromboembolism.
Contraindications: See SPC.
Dosage and administration: For subcutaneous injection into a pinched-up fold of the skin of the abdominal wall or on the front of the thigh. Unless otherwise prescribed, 0.25ml once daily for the primary prophylaxis of thrombosis and embolism in patients undergoing surgery. The first injection should be given two hours before surgery. The duration of therapy depends on the nature of the underlying disease and the length of time the patient is at risk (immobilised). Treatment is administered until the patient is fully mobilised. In uncomplicated cases, therapy is normally given for seven days. A platelet count must be done prior to administration and, at the minimum, on days one and four of treatment. Thereafter, twice weekly during the first three weeks after starting treatment.
Pregnancy, reviparin is not recommended.
Children, safety and efficacy has not been established.
Overdosage: Overdosage with low molecular weight heparin results in hypocoagulability. Slow intravenous injection of the antidote, protamine, immediately and completely neutralises reviparin's anti-Factor Xa activity while partly neutralising anti-Factor IIa activity. The protamine dose must be adjusted to the reviparin dose. About 17.5mg of protamine is required to neutralise a single dose of reviparin (0.25ml).
Precautions: Reviparin must not be administered intramuscularly. Other medications requiring intramuscular injections should be avoided during reviparin treatment. Plasma potassium should be measured in patients at risk before starting heparin therapy and monitored regularly thereafter, particularly if treatment is prolonged beyond about seven days.
Drug interactions: Reviparin's potential to interact with other substances has not yet been investigated. In the light of data on unfractionated heparin and other fractionated heparins, the possibility of interaction with the following substances should be considered: substances affecting blood coagulation, non-steroidal anti-inflammatory drugs, sulphinpyrazone, nitroglycerin infusion, drugs which cause displacement from plasma protein binding (see SPC for further details). Drugs that raise serum potassium levels should only be taken under close medical supervision. Further interactions should not be precluded, for example with drugs such as antihistamines, cardiac glycosides and tetracyclines.
Side effects: Local tissue reaction, raised incidence of bleeding, thrombocytopenia, hypoaldosteronism (which may result in an increase in plasma potassium). Rarely, hypersensitivity reactions, alopecia (usually transient). Osteoporosis has been associated with long-term heparin treamtent.
Net price: 5 x 0.25ml prefilled syringes £18.15.
Supplier: ICN Pharmaceuticals Ltd, 1 Elmwood, Chineham Business Park, Crockford Lane, Basingstoke, Hampshire RG24 8WG. Tel 01256 707744, fax 01256 707334.
Legal class: POM.