Tenecteplase Dosing for Acute Myocardial Infarction
The recommended dose of tenecteplase (TNK-tPA) for acute myocardial infarction is administered as a single intravenous bolus based on patient weight: 30 mg if <60 kg, 35 mg if 60 to <70 kg, 40 mg if 70 to <80 kg, 45 mg if 80 to <90 kg, and 50 mg if ≥90 kg. 1, 2, 3, 4
Administration Protocol
- Tenecteplase should be administered as a single intravenous bolus over 5-10 seconds 3, 4
- The drug exhibits a biphasic elimination with an initial half-life of 17-24 minutes and a terminal half-life of 65-132 minutes 5
- This prolonged half-life (compared to alteplase's 3.5 minutes) allows for the single bolus administration rather than an infusion 5, 6
- Tenecteplase has higher fibrin specificity and resistance to plasminogen activator inhibitor-1 compared to alteplase 6
Weight-Based Dosing Table
| Patient Weight (kg) | Tenecteplase Dose (mg) | Volume to Administer (mL) |
|---|---|---|
| < 60 | 30 | 6 |
| 60 to < 70 | 35 | 7 |
| 70 to < 80 | 40 | 8 |
| 80 to < 90 | 45 | 9 |
| ≥ 90 | 50 | 10 |
Required Adjunctive Therapy
- Aspirin: 150-300 mg orally or 80-150 mg IV if oral ingestion is not possible, followed by maintenance dose of 75-100 mg/day 1, 2, 3
- Clopidogrel: Loading dose of 300 mg orally if aged ≤75 years, followed by maintenance dose of 75 mg/day 1, 2, 3
- Anticoagulation is required until revascularization or for the duration of hospital stay (up to 8 days) 2, 3
- Enoxaparin (preferred): For patients <75 years, 30 mg IV bolus followed by 1 mg/kg SC every 12 hours; for patients >75 years, no IV bolus with first SC dose of 0.75 mg/kg 1
- Unfractionated heparin: 60 U/kg IV bolus (maximum 4000 U) followed by IV infusion of 12 U/kg/hr (maximum 1000 U/hr) for 24-48 hours, targeting aPTT 50-70 seconds 1
Post-Administration Management
- Monitor for signs of successful reperfusion: relief of symptoms, maintenance of hemodynamic/electrical stability, and reduction of ST-segment elevation by at least 50% at 60-90 minutes 2
- Transfer to a PCI-capable center following fibrinolysis is indicated in all patients 2, 3
- Consider rescue PCI immediately if fibrinolysis has failed (<50% ST-segment resolution at 60 minutes) 2
- Angiography with a view to revascularization is recommended after successful fibrinolysis, optimally between 3-24 hours 1, 2
Clinical Efficacy and Safety
- Tenecteplase has demonstrated equivalent efficacy to alteplase in the ASSENT-2 trial with 30-day mortality rates of approximately 6.2% for both agents 4, 6
- The rate of non-cerebral bleeding was lower with tenecteplase than with alteplase (26.43% vs 28.95%) 6
- Intracranial hemorrhage rates were similar between tenecteplase and alteplase (0.9% for both) 4
Special Considerations and Contraindications
- Avoid tenecteplase in patients >75 years when using low molecular weight heparin as ancillary therapy 2
- Avoid low molecular weight heparin in patients with significant renal dysfunction (serum creatinine >2.5 mg/dL in men or >2.0 mg/dL in women) 2
- The combination of tenecteplase, aspirin, enoxaparin, and clopidogrel has been extensively studied as part of a pharmacoinvasive strategy 1, 2
- Absolute contraindications include any prior intracranial hemorrhage, known structural cerebral vascular lesion, ischemic stroke within 3 months, suspected aortic dissection, active bleeding, significant closed-head trauma within 3 months, and severe uncontrolled hypertension 3