Tranexamic acid - an old drug still going strong and making a revival.
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Experience with tranexamic acid, an indirect fibrinolytic inhibitor, started as soon as it was released from Shosuke Okamoto's lab in the early 1960s. It was first prescribed to females with heavy menstrual blood loss and to patients with hereditary bleeding disorders. Soon the indications were widened to elective surgery because of its blood saving effects. Contraindications are few, most important is ongoing venous or arterial thrombosis and allergy to tranexamic acid, and the doses has to be reduced in renal insufficiency. In randomized controlled trials, however, patients with other risk factors are excluded as well (patients with history of cardiovascular disease, thromboembolism, bleeding diathesis, renal failure with creatinine >250μmol/L, pregnancy, and patients on treatment with anticoagulants). Recent meta-analyses of several randomized controlled trials in orthopedic arthroplasty have shown that tranexamic acid reduces peri- and postoperative blood loss, blood transfusion requirements and reoperations caused by bleedings. In general, the preoperative dose was 10-15mg/kg i.v. (or 1g), followed or not, by one or two doses, some as continuous infusion i.v. To validate relationship between dose and effect more data are needed. No evidence was found of increased thromboembolic accidents or other adverse events in the patients on tranexamic acid compared to the control groups. In major cardiac surgery tranexamic acid has been used in a large number of controlled trials with various dosing schemes in which the highest dosages seem to be associated with neurotoxicity; therefore a maximum total dose of 100mg/kg especially in patients over 50years of age is recommended by ISMICS (International Society for Minimally Invasive Cardiothoracic Surgery). Other indications for tranexamic acid are reviewed here as well. In recent years the extensive trial in severe trauma with massive bleedings using tranexamic acid was presented, CRASH-2 (Clinical Randomisation of an Antifibrinolytic in Significant Haemorrhage) comprising more than 20,000 patients. It showed that the survival was increased when tranexamic acid was given early after the accident compared to placebo; further studies are taking place is this field to get more information. Of utmost importance is the ongoing WOMAN (World Maternal Antifibrinolytic) a randomized, double-blind, placebo controlled trial among 15,000 with clinical diagnosis of postpartum haemorrhage bearing in mind that each year a large number of women in low and middle income countries, die from causes related to childbirth. In summary, we consider tranexamic acid is a drug of great value to reduce almost any kind of bleeding, it is cheap and convenient to use and has principally few contraindications. It may be added, that tranexamic acid is included in the WHOs list of essential medicines.