If your stroke is caused by a blood clot (ischaemic stroke), you may be treated with a clot-busting drug to try to disperse the clot and return the blood supply to your brain. 

The medicine itself is called alteplase, or recombinant tissue plasminogen activator (rt-PA). The process of giving this medicine is known as thrombolysis.

Thrombolysis can break down and disperse a clot that is preventing blood from reaching your brain.

For most people thrombolysis needs to be given within four and a half hours of your stroke symptoms starting. In some circumstances, your doctor may decide that it could still be of benefit within six hours. However the more time that passes, the less effective thrombolysis will be. This is why it’s important to get to hospital as quickly as possible when your symptoms start.
After thrombolysis, 10% more patients survive and live independently. Despite its benefits, there is a risk that thrombolysis can cause  bleeding in your brain. This happens to about one in 25 people within seven days of thrombolysis, and this can be fatal in about one in 40 cases. The sooner you are treated, the better the chances of improvement, and the lower the risk of harm.
Who can have thrombolysis?

Not everyone who has an ischaemic stroke is suitable for thrombolysis. At present around 12% of people who are admitted to hospital with a stroke are eligible to receive it. If you are not suitable, it may be because:

  • you had a bleed in in the brain
  • you do not know or cannot tell doctors when your symptoms began
  • you do not reach hospital in time
  • you have a bleeding disorder
  • you have recently had major surgery
  • you have had another stroke or head injury within the past three months
  • your current medication is not compatible with alteplase.


Thrombectomy is a treatment that physically removes the clot. It usually involves inserting a mesh device into an artery in your groin, moving it up to the brain, and pulling the clot out. It only works with people where the blood clot is in a large artery, but in these people it is more effective than thrombolysis. Like thrombolysis, it has to be carried out within hours of a stroke starting. As yet this is only available in a small number of UK hospitals, but it may become more widespread.

Other early treatments

Unless your stroke has been caused by a bleed it is likely that you will be given aspirin or an alternative anti-platelet drug like clopidogrel as soon as possible, and certainly within 24 hours of being diagnosed. This makes the blood less sticky and stops clots forming, which helps to prevent another stroke.