Nursing care
Tissue Plasminogen Activator: what to check before you give it
Written and reviewed by Dana Whitfield, RN, MSN · 5 min read · Updated September 2026
Short answer
Tissue plasminogen activator (tPA, alteplase) dissolves clots by converting plasminogen to plasmin, restoring blood flow in ischaemic stroke or PE. The nurse's job is timing and screening: confirm onset within the eligible window, run the exclusion checklist, and rule out haemorrhagic stroke, which is an absolute contraindication. Bleeding risk drives every intervention that follows.
Mechanism, simply
Alteplase is a recombinant tissue plasminogen activator. It binds fibrin within a clot and converts trapped plasminogen into plasmin, the enzyme that breaks down the fibrin mesh holding the clot together. The clot dissolves, and perfusion returns to the tissue it was blocking.
This is a targeted but not a selective drug. Plasmin does not stay inside the clot; it circulates and degrades fibrinogen and clotting factors throughout the body. That systemic effect is why the drug that restores flow to a stroke-affected brain is the same drug that can cause bleeding anywhere, from gums to retroperitoneum. Efficacy and risk come from the same mechanism, not two separate properties.
Indications you will see on the ward
Acute ischaemic stroke is the indication tested most heavily, because it is the one where minutes change the outcome and the nurse is often the person tracking the clock. Alteplase is also used for acute ST-elevation MI when primary PCI is not rapidly available, for massive pulmonary embolism with haemodynamic instability, and for catheter or central line occlusion at lower, localised doses.
Each indication carries its own timing rule, and the rules are not interchangeable. Ischaemic stroke treatment is generally considered within 3 hours of symptom onset, extending to 4.5 hours for a subset of patients who meet additional criteria. Confirm which protocol and which window your facility is using before you assume a figure from one indication applies to another.
Assessment before administration
Establishing the exact time of symptom onset, or last known well, is the first nursing task, and it is often the hardest one. Ask family and witnesses directly; a vague answer changes the eligibility calculation. This time, not the time the patient arrived, is what the treatment window is measured against.
The exclusion checklist is a nursing responsibility, not a formality to sign off. Screen for recent surgery or trauma, active internal bleeding, anticoagulant use with an elevated INR, platelet count, blood pressure above the treatment threshold, and any history of intracranial haemorrhage. A non-contrast CT scan must confirm the stroke is ischaemic, not haemorrhagic, before the drug is ever drawn up. A haemorrhagic stroke is an absolute contraindication: giving a clot-dissolving drug into an active bleed in the brain turns a survivable event into a fatal one. Blood pressure needs to be brought within range before administration and held there throughout the infusion.
Toxicity and the antidote
The principal toxicity is haemorrhage, most seriously intracranial. Watch for a sudden headache, new or worsening neurological deficit, vomiting, or an acute drop in level of consciousness during or after the infusion; any of these warrants stopping the drug and getting an urgent CT scan.
There is no specific antidote. Management is supportive: stop the infusion, correct coagulopathy with cryoprecipitate or fresh frozen plasma, and give an antifibrinolytic such as tranexamic acid if ordered. Because reversal is difficult and incomplete, the exclusion screening before the dose is where the real protection lies, not the response after a bleed starts.
Interactions that matter
Anticoagulants and antiplatelet agents compound the bleeding risk directly. A patient on warfarin, a direct oral anticoagulant, heparin, or aspirin needs their most recent coagulation results reviewed before tPA is given, and current anticoagulant use above a defined threshold is itself an exclusion criterion.
Avoid giving other agents that increase bleeding risk during the infusion and for the period afterward specified by protocol, typically 24 hours: no intramuscular injections, no arterial punctures, no unnecessary venepuncture, and no additional anticoagulants until repeat imaging confirms no haemorrhage. Nasogastric tubes and urinary catheters, if needed, should generally be placed before the infusion starts rather than during or immediately after.
What the patient must be told
Explain, in terms the patient or family can absorb quickly, that this drug works by dissolving the clot causing the stroke or blockage, and that its benefit is tied directly to how soon it is given. Set the expectation that neurological checks will happen frequently, often every 15 minutes initially, and that this frequency reflects monitoring for bleeding, not a worsening condition.
Tell them to report any new headache, visual change, bleeding from gums or injection sites, or blood in urine or stool immediately, rather than waiting for the next scheduled check. Reinforce that no other medications, herbal supplements, or over-the-counter analgesics should be taken during the post-infusion restricted period without asking first, since even aspirin adds meaningfully to bleeding risk at this stage.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our neurological practice questions are the closest set to what this page covers.
Common questions
What is the time window for giving tPA in ischaemic stroke?
Generally within 3 hours of symptom onset, extendable to 4.5 hours for patients who meet additional eligibility criteria. Onset time is defined as the last time the patient was known to be well, not the time symptoms were noticed or the time of arrival.
Why is haemorrhagic stroke an absolute contraindication for tPA?
tPA works by dissolving clots, and in a haemorrhagic stroke the problem is bleeding, not clotting. Giving it would accelerate the bleed rather than stop the pathology, so a non-contrast CT confirming an ischaemic, not haemorrhagic, cause is required before administration.
What vital sign do you monitor most closely during tPA infusion?
Blood pressure. It must be brought below the treatment threshold before the infusion and kept there throughout, because uncontrolled hypertension raises the risk of intracranial haemorrhage during thrombolysis.
Can you give tPA to a patient on warfarin?
Only if their INR falls within the accepted range specified by protocol; an elevated INR from anticoagulant use is an exclusion criterion because it compounds the bleeding risk tPA already carries.
What do you do if a patient develops a sudden headache during tPA infusion?
Stop the infusion immediately and obtain an urgent CT scan to rule out intracranial haemorrhage. A sudden headache, new neurological deficit, or drop in consciousness during infusion is treated as a bleed until proven otherwise.