About This Calculator

The Alteplase Stroke Dose Calculator is a clinical support tool designed for healthcare professionals to determine the appropriate dosage of alteplase (tissue plasminogen activator, or tPA) for adult patients experiencing an acute ischemic stroke. The calculations are based on the weight-based dosing recommendations from the American Heart Association/American Stroke Association (AHA/ASA) guidelines. This tool streamlines the calculation of total dose, bolus, and infusion rates to ensure accurate and timely administration in critical care settings.

Calculator Outputs Explained

Upon entering the patient's weight, the calculator provides a complete dosing regimen:

• Patient Weight Used for Calculation: Displays the weight in kilograms (kg) used for the dose calculation. This value is capped at 100 kg, even if the patient's actual weight is higher.
• Total Alteplase Dose: The total amount of alteplase in milligrams (mg) to be administered, calculated as 0.9 mg/kg, up to a maximum of 90 mg.
• Bolus Dose (10%): The initial dose to be given as an intravenous (IV) push over one minute. The tool provides this value in both mg and milliliters (mL), assuming a 1 mg/mL concentration.
• Infusion Dose (90%): The remaining portion of the total dose to be administered via a continuous IV infusion over 60 minutes. This is also shown in mg and mL.
• Infusion Pump Rate: The rate at which to set the infusion pump, typically in mL/hour, to deliver the infusion dose over the correct duration of one hour.

How to Use the Calculator

Follow these simple steps for an accurate dose calculation:

1. Confirm Eligibility: Ensure the patient meets all institutional and guideline-based inclusion criteria for thrombolytic therapy and has no contraindications.
2. Enter Patient Weight: Input the patient's current weight into the designated field.
3. Select Units: Choose the appropriate weight unit, either kilograms (kg) or pounds (lbs). The tool will automatically convert lbs to kg.
4. Calculate: Click the "Calculate Dose" button to generate the results.
5. Verify and Administer: Cross-reference the calculated doses with institutional protocols and the official prescribing information before preparing and administering the medication.

Dosing Overview

The standard alteplase dosing for acute ischemic stroke in adults is as follows:

• The recommended total dose is 0.9 mg/kg.
• The maximum total dose is 90 mg, regardless of how much the patient weighs over 100 kg.
• 10% of the total dose is administered as an initial IV bolus over 1 minute.
• The remaining 90% of the total dose is infused intravenously over 60 minutes.
• Alteplase is typically reconstituted to a final concentration of 1 mg/mL for administration.

Switching Medications

Switching is not applicable. Alteplase for acute ischemic stroke is a single, one-time emergency therapy. It is not part of a maintenance or long-term dosing schedule that would involve switching to or from other medications in the same context.

Missed Dose

The concept of a missed dose does not apply. Alteplase is administered as a single IV bolus followed immediately by a 60-minute infusion under continuous medical supervision in an emergency setting. There is no ongoing dosing schedule.

Safety Alerts

Alteplase administration carries significant risks, primarily bleeding. It must only be used by qualified physicians in a setting with appropriate diagnostic and supportive resources.

• Most Common Risk: The most frequent and serious adverse reaction is bleeding, including intracranial hemorrhage (ICH), which can be fatal.
• Contraindications: Do not administer to patients with active internal bleeding, recent (within 3 months) serious head trauma or stroke, history of intracranial hemorrhage, uncontrolled hypertension (SBP >185 mmHg or DBP >110 mmHg), or known bleeding diathesis.
• Monitoring: Patients must be monitored closely for signs of bleeding, angioedema, and other hypersensitivity reactions during and after administration. Frequent neurological assessments and blood pressure monitoring are critical.

Frequently Asked Questions (FAQ)

References

1. Powers WJ, Rabinstein AA, Ackerson T, et al. 2019 Update to the 2018 Guidelines for the Early Management of Acute Ischemic Stroke: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke. 2019;50(12):e344-e418. Link
2. Activase® (alteplase) Prescribing Information. Genentech, Inc. South San Francisco, CA. Link
3. U.S. Food and Drug Administration (FDA). Drugs@FDA: ACTIVASE (alteplase). Link
4. European Medicines Agency (EMA). Actilyse (alteplase) Summary of Product Characteristics. Link