What is the recommended dose of Alteplase (tissue plasminogen activator) for an adult patient with acute ischemic stroke?

Alteplase Dosing for Acute Ischemic Stroke

The recommended dose of alteplase for acute ischemic stroke is 0.9 mg/kg (maximum 90 mg total), administered as 10% IV bolus over 1 minute followed by 90% IV infusion over 60 minutes. 1, 2

Standard Dosing Protocol

• Calculate total dose: 0.9 mg/kg body weight with an absolute maximum of 90 mg regardless of patient weight 1, 2
• Initial bolus: 10% of total dose (0.09 mg/kg) given as IV push over exactly 1 minute 1, 2, 3
• Continuous infusion: Remaining 90% of total dose (0.81 mg/kg) administered IV over 60 minutes 1, 2, 3

This dosing regimen is identical whether treating within 0-3 hours or 3-4.5 hours from symptom onset. 1

Critical Pre-Administration Requirements

Only blood glucose must be checked before initiating alteplase—do not delay treatment waiting for other laboratory results. 1, 2, 3

• Blood glucose must be >50 mg/dL (>3.3 mmol/L); treat hypoglycemia with IV dextrose before alteplase 1, 3
• Blood pressure must be reduced to <185/110 mmHg before starting thrombolysis 1, 2, 3
• CT scan must confirm absence of intracranial hemorrhage 1, 3

Timing Considerations

Initiate alteplase immediately after CT confirms ischemic stroke, targeting door-to-needle time <60 minutes in 90% of patients, with optimal median of 30 minutes. 2, 3

• 0-3 hour window: Level A recommendation—alteplase should be offered to all eligible patients meeting NINDS criteria 1
• 3-4.5 hour window: Level B recommendation—alteplase should be considered for patients meeting ECASS III criteria 1
• Extended window (4.5-24 hours): Recent 2025 HOPE trial data shows benefit when salvageable tissue is identified on perfusion imaging, though this represents emerging evidence 4

For patients >80 years old presenting in the 3-4.5 hour window, alteplase is safe and can be as effective as in younger patients. 1 However, additional exclusion criteria apply in the 3-4.5 hour window: exclude patients on oral anticoagulants regardless of INR, NIHSS >25, or history of both stroke and diabetes. 2, 3

Maximum Dose Limit Rationale

The 90 mg maximum dose limit is evidence-based and should not be exceeded. 5 Patients weighing >100 kg receive a lower per-kilogram dose (approximately 0.82 mg/kg vs 0.90 mg/kg), but research demonstrates this is appropriate—these patients actually have higher rates of symptomatic intracranial hemorrhage (2.6% vs 1.7%) despite the lower per-kilogram dose, while achieving similar functional independence. 5

Critical Dosing Errors to Avoid

Never use the myocardial infarction alteplase dosing protocol for stroke—this is a potentially catastrophic error. 2 The MI protocol uses different dosing (100 mg total with front-loaded bolus), which is inappropriate and dangerous for stroke patients.

Always verify you are implementing the stroke-specific protocol: 0.9 mg/kg (max 90 mg), 10% bolus over 1 minute, 90% infusion over 60 minutes. 2, 3

Relationship to Mechanical Thrombectomy

Do NOT wait to evaluate response to IV alteplase before proceeding with catheter angiography for mechanical thrombectomy if indicated. 1, 2, 3 Eligible patients should receive IV thrombolysis even if mechanical thrombectomy is being considered, and both should proceed simultaneously without delay. 1

Special Population Considerations

For patients on direct oral anticoagulants (DOACs), do not routinely administer alteplase except in comprehensive stroke centers with DOAC level testing and reversal agents available. 2, 3 Standard 0.9 mg/kg dosing carries uncertain safety in DOAC patients. 1

For patients with warfarin use and INR ≤1.7 and/or PT <15 seconds, alteplase may be reasonable. 1

Low-Dose Alteplase (Asian Populations)

While some Asian countries use lower doses (0.6 mg/kg), the standard 0.9 mg/kg dose is recommended by all major international guidelines including AHA/ASA, World Stroke Organization, and ACEP. 1 Recent research suggests low-dose may have comparable effectiveness in Asian patients <70 years old, but standard-dose appears superior in patients ≥70 years, particularly those with cardioembolism or atrial fibrillation. 6, 7 Given guideline consensus, use standard 0.9 mg/kg dosing unless institutional protocols specifically mandate otherwise.