A drug used for heavy periods could benefit patients with strokes caused by dangerous brain bleeds, experts says.
Currently, there is no effective drug treatment.
A trial in The Lancet found tranexamic acid stemmed bleeding and reduced the risk of death in the early days following a haemorrhagic stroke.
Although it did not equate to less disability at three months, researchers are still hopeful about its use as a stroke therapy.
Up to a fifth of strokes are bleeds.
They account for nearly a half of all stroke deaths worldwide.
Those who do survive may be left with debilitating disabilities, including paralysis and difficulty with their speech.
Carolyn Danbury was 32 when she had a stroke. She had been out Christmas shopping at the time.
"I felt almost a bit of a head rush," she says. "I didn't quite feel right.
"I went to pick up a gift bag with my left hand and I couldn't grasp it. I knew something was wrong. I felt like I was drunk really. My left leg started to drag. I was panicking."
She tried to ask for help, but the words wouldn't come out.
"I was trying to say, 'Please help me, something is wrong,'" she says. "I could say it in my head, but I just couldn't say it."
An emergency scan at hospital revealed Carolyn had a bleed on her brain.
She was offered the option to take part in the tranexamic acid trial and accepted. She still doesn't know if she received the drug itself or a dummy injection, but she has made a good recovery.
Half of the 2,325 people who took part in the trial were given tranexamic acid and the other half were given a placebo so that the researchers could reliably measure what effect the treatment had.
Researcher Dr Nikola Sprigg, from the University of Nottingham, said: "Tranexamic acid is a drug that has been around for a long time. It's effective in other bleeding conditions."
It is already used (in tablets) for treating heavy periods and (by injection) for controlling dangerous bleeding during childbirth or severe trauma.
"In the stroke patients it reduced the amount of bleeding in the brain," Dr Sprigg said. "It also reduced the amount of people that died in the first week after bleeding, which is the emergency period."
Less bleeding should mean less damage and disability, and fewer deaths.
But the study did not find any difference between the two patient groups on these measures at three months.
Prof Sprigg said: "Future work is going to need to focus on getting patients to hospital quicker and getting the treatment quicker – probably within three or four hours."
The Stroke Association, which funded earlier stages of the trial, said: "Currently, treatment for haemorrhagic stroke is very limited so we are excited by the findings of this study into bleeding that happens within the brain. We hope there will now be further research into how this relatively cheap and widely available drug could be used to potentially save lives and improve long-term recovery from this type of stroke. "
Know the signs of a stroke – act fast
- face – has it fallen on one side?
- arms – can they be raised?
- speech – is it slurred?
- time – if you notice any of these dial 999
A stroke happens when the blood supply to the brain is disrupted, either by a blood clot blocking the supply or a bleed.
It's a medical emergency that needs immediate attention.
The sooner somebody who is having a stroke receives help, the better their chances of a good recovery.