Guidelines for IV Thrombolysis in Acute Ischemic Stroke

Time Windows and Eligibility

The American Heart Association recommends administering IV alteplase to all eligible patients with acute ischemic stroke presenting within 4.5 hours of symptom onset or last known well, with a target door-to-needle time under 60 minutes 1, 2, 3
All patients with measurable neurological deficit should receive IV alteplase within 3 hours of symptom onset, regardless of stroke severity or extent of early ischemic changes on imaging 1, 2, 3
Patients with mild symptoms that are potentially disabling may be considered for treatment, though the risk-benefit ratio requires careful assessment 1, 4

The standard dose is 0.9 mg/kg (maximum 90 mg total): give 10% as IV bolus over 1 minute, then infuse remaining 90% over 60 minutes 5, 3, 6
Door-to-needle time should be <60 minutes in 90% of patients 2, 3
Only blood glucose measurement must precede alteplase initiation—do not delay for other laboratory tests 3

BP must be lowered to <185/110 mmHg before initiating thrombolysis 2, 3, 6
Monitor BP every 15 minutes during and for 2 hours after infusion, then every 30 minutes for 6 hours, then hourly until 24 hours 5

Do not administer IV alteplase if any of the following are present: CT or MRI showing intracranial hemorrhage 2, 6
History of intracranial hemorrhage 1, 4, 2
Direct oral anticoagulants (DOACs) within 48 hours unless appropriate laboratory tests are normal 1, 4

Warfarin use with INR ≤1.7 and PT <15 seconds: may treat 7, 8
DOACs: do not treat if taken within 48 hours unless specific coagulation assays are normal AND renal function is normal 1, 4
Glycoprotein IIb/IIIa inhibitors should not be given concurrently with alteplase 1, 4

Eligible patients should receive IV alteplase even if mechanical thrombectomy is being considered 2, 3
Do not observe for clinical response to alteplase before initiating thrombectomy evaluation—any delay worsens outcomes 2, 3

Admit to intensive care or stroke unit 5
Neurological assessments every 15 minutes during and for 2 hours after infusion 5
Obtain CT or MRI at 24 hours after alteplase before starting anticoagulants or antiplatelet agents 5

Never delay treatment for non-essential laboratory tests—only glucose is required before initiating alteplase 2, 3
Never exclude patients >80 years in the 3-4.5 hour window—this is outdated practice 1, 2
Never wait to assess alteplase response before initiating thrombectomy evaluation 2, 3