Individualisation of oral anticoagulant therapy.

The hepatic synthesis of vitamin K dependent coagulation factors is modified by oral anticoagulant drugs, resulting in the release of functionally deficient coagulation factors into the circulation and consequently anticoagulation. Since their introduction into clinical medicine over 30 years ago, both clinical and scientific evidence has demonstrated the value of oral anticoagulants in the treatment and prophylaxis of venous thrombosis. In the treatment of arterial disease, however, both the indications for and usefulness of oral anticoagulants remain very much in doubt despite their widespread use in the 1950s and 1960s and in numerous clinical trials. The initiation and continuation of oral anticoagulant therapy is a co-operative venture involving the patient, the clinician and the laboratory. The clinician must have a thorough knowledge of the indications for and contraindications to the use of these drugs, and regular, accurate laboratory control is essential if haemorrhage, the major side effect, is to be avoided or reduced to a minimum. The patient must bear the responsibility for regular clinic attendance, abstinence from proprietary medications, and must immediately seek medical advice if any sign of haemorrhage occurs.