tPA Calculator — Alteplase Dose for Acute Ischemic Stroke
Compute the standard Alteplase (tPA) dose for acute ischemic stroke per the NINDS protocol: 0.9 mg/kg up to a maximum of 90 mg, split into a 10% IV bolus over 1 minute and a 90% IV infusion over 60 minutes.
kg
0.9 mg/kg, maximum 90 mg · NINDS acute ischemic stroke protocol
- 1
Weight-based dose
0.9 mg/kg × 70 kg = 63Actual body weight is used, not ideal or adjusted body weight. - 2
Total dose (90 mg cap applied)
min(63, 90) = 63
此計算機如何運作？
Alteplase (tPA) for acute ischemic stroke: 0.9 mg/kg actual body weight, maximum 90 mg total. Give 10% as an IV bolus over 1 minute, then 90% by IV infusion over 60 minutes. Treatment window is 3–4.5 hours from symptom onset for eligible patients. Physician supervision required at all times.
公式
How this is calculated
Alteplase (tPA — tissue plasminogen activator) is the only FDA-approved thrombolytic for acute ischemic stroke. It activates the enzyme plasmin, which dissolves the fibrin clot occluding a cerebral artery. The NINDS protocol, validated by landmark randomised controlled trials, specifies 0.9 mg/kg of actual body weight up to an absolute ceiling of 90 mg — above this threshold, the risk of symptomatic intracranial haemorrhage rises without additional benefit.
The total dose is divided into two parts: 10% is administered as a rapid IV push over approximately 1 minute to achieve therapeutic plasma concentrations quickly; the remaining 90% follows as a continuous IV infusion over 60 minutes. Actual (not ideal or adjusted) body weight is used because total body mass correlates with drug distribution and clearance, though the 90 mg cap means patients above roughly 100 kg receive a lower effective dose per kilogram.
This calculator is for acute ischemic stroke only. Strict eligibility criteria apply — typically symptom onset within 3–4.5 hours, NIHSS ≥ 4, absence of contraindications. Major contraindications include recent surgery or trauma, active internal bleeding, uncontrolled hypertension (> 185/110 mmHg), prior intracranial haemorrhage, and therapeutic anticoagulation. All administration decisions require direct physician involvement.
常見問題
NINDS and subsequent clinical trials established 90 mg as the safety ceiling. Higher doses were associated with increased rates of symptomatic intracranial haemorrhage without improved functional outcomes. For patients weighing 100 kg or more, the 0.9 mg/kg formula would exceed 90 mg, so the cap applies and the effective dose rate falls below 0.9 mg/kg.
The original FDA approval covers treatment within 3 hours of symptom onset. The ECASS III trial extended eligibility to 4.5 hours for selected patients — excluding those aged > 80, on oral anticoagulants, with NIHSS > 25, or with combined prior stroke and diabetes. The mantra 'time is brain' reflects that each minute of delay reduces the chance of a good outcome.
No. Alteplase dosing for massive pulmonary embolism (100 mg IV over 2 hours) and STEMI (weight-based accelerated regimens) is entirely different from the stroke protocol. Always use the correct indication-specific protocol and confirm with a physician. This tool applies only to acute ischemic stroke.
TG we-Calculate Editorial Team. (2026). tPA Calculator — Alteplase Dose for Acute Ischemic Stroke [Online calculator]. TG we-Calculate. https://we-calculate.com/zh-tw/calculator/tpa-calculator
TG we-Calculate Editorial Team. "tPA Calculator — Alteplase Dose for Acute Ischemic Stroke." TG we-Calculate. 2026. https://we-calculate.com/zh-tw/calculator/tpa-calculator.
TG we-Calculate Editorial Team, "tPA Calculator — Alteplase Dose for Acute Ischemic Stroke," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/zh-tw/calculator/tpa-calculator
@misc{wecalculate_tpa_calculator, title = {tPA Calculator — Alteplase Dose for Acute Ischemic Stroke}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/zh-tw/calculator/tpa-calculator}}, year = {2026}, note = {TG we-Calculate} }
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