Activase FAQs

By: Katy Hendrickson, BSN, RN, SCRN, Stroke Coordinator

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Activase (Alteplase) or tPA and Stroke FAQs

What is tPA?

It is a thrombotic drug recommended as the standard of care in ischemic stroke. It works by breaking up the clot in the brain, thereby restoring blood flow and minimizing damage to surrounding tissue.

When can tPA be used?

When treating ischemic stroke, the sooner tPA is initiated the better, but it can be utilized as far as 4.5 hours from a person’s “last known normal”

What is “last known normal”

This is the time that someone can identify as seeing a patient in their normal state and baseline mentation. This is not when the symptoms begin. It is important to know this information as medication administration is based on the length of time a stroke has been progressing.

How does tPA work?

Activase is an enzyme that is produced by recombinant DNA. When it is administered it binds to the fibrin protein threads of a thrombus converting enmeshed plasminogen to plasmin (fibrinolysis). This essentially means that a clot is dissolved and blood flow is restored.

What is the risk of using tPA?

The risk of using this medication is that a person bleeds. That bleeding may happen anywhere, but the biggest risk is that the stroke that started as a clot converts to a bleed. This only happens in about 6% of cases, but is something that should be considered when deciding if you or a loved one wants to receive tPA.

Why should I use tPA?

Activase is the only FDA approved medication indicated for the treatment of acute stroke. It has been approved for the treatment of ischemic stroke since 1996, and is currently the standard of care for these patients. Generally, when a patient starts experiencing the symptoms of a stroke, it is because brain cells are beginning to die, the longer the brain goes without blood flow and oxygen the more brain cells die. tPA can break up the clot obstructing this blood flow and stop further cell death. In the below picture the red “core” is the cells that have already died once a person begins experiencing stroke symptoms. The surrounding green area called the “penumbra” is the area that will be affected if tPA is not given, but can be salvaged if blood flow is restored.

Why is it important to come to the hospital immediately upon symptoms?

Time is brain, 2 million brain cells die every minute during a stroke. tPA can only be given within 4.5 hours of last known normal. If a person waits to receive treatment, their options are limited and they are often left with more disability.

Should I drive or take an ambulance to the emergency room?

Always call 911 and take an ambulance. Even if you think you could get here faster on your own, ambulances can call a “stroke alert” to the accepting emergency room ahead of time, so by the time you arrive all necessary personnel are awaiting your arrival. They can also preform many preliminary testing while en route, speeding up your time to treatment.