London School of Hygiene & Tropical Medicine

An hour can make the difference between life and death when using tranexamic acid to treat injured patients with severe bleeding, a study by researchers at the London School of Hygiene & Tropical Medicine suggests.

New analysis of the CRASH-2 trial shows that rapid treatment – preferably within an hour of injury – dramatically cuts bleeding deaths in injured patients.

The discovery, published in The Lancet, has already led to the British military using the therapy in the first hour to treat wounded soldiers in Afghanistan.

According to the scientists, to ensure that trauma patients benefit from the crucial early treatment, the NHS may need to consider giving tranexamic acid in ambulances.

If treatment is delayed beyond three or four hours after the injury, it is unlikely to be effective and might even be harmful, the research shows.

The researchers, led by Professor Ian Roberts, said: “These results show that early administration of tranexamic acid is critical – they have major implications for trauma care provision worldwide.”

The CRASH-2 trial involved 20,211 adult trauma patients in 40 countries with, or at risk of, significant bleeding who were randomly assigned to either tranexamic acid or a placebo within eight hours of injury.

First published in The Lancet last June, the trial found that administration of tranexamic acid – which reduces clot breakdown and is used to treat heavy periods - reduced mortality by around 10%.

However, in the latest analysis, the authors looked at subgroups of patients who had received tranexamic acid within an hour of the injury; between one and three hours; or more than three hours, in order to explore the relationship between timing of administration of the drug and its effect.

Early treatment (within an hour of injury) reduced the risk of death due to bleeding by more than 30%. Treatment given between one and three hours cut the risk of bleeding death by 20% but there was no benefit if treatment was delayed beyond 3 or 4 hours.

Professor Roberts said: “In patients with severe bleeding whether from accidents or violence, rapid treatment with tranexamic acid is vital - an hour could mean a lifetime.”