Administration & posology

Thrombolytic treatment with intravenous Tenecteplase (TNK-tPA, Metalyse^®) is an effective evidence-based treatment for acute myocardial infarction and recent left bundle branch block, which should be initiated as soon as possible after onset of symptoms. It is the first thrombolytic that can be administered in a single bolus thus offering the fastest administration of a thrombolytic to date in the treatment of AMI. Tenecteplase (TNK-tPA, Metalyse^®) should be prescribed by physicians experienced in the use of thrombolytic treatment and with the facilities to monitor that use.

Tenecteplase (TNK-tPA, Metalyse^®) should be administered on the basis of estimated body weight, with a maximum dose of 10,000 units (50 mg tenecteplase). Estimation of body weight is very effective: in the ASSENT-2 trial, more than 96% of patients received the planned dose of tenecteplase based on estimation of body weight. The volume required to administer the correct dose can be calculated from the scheme in the table.

The required dose should be administered as a single intravenous bolus over 5–10 seconds.

A pre-existing intravenous line may be used for administration of Tenecteplase (TNK-tPA, Metalyse^®) in 0.9% sodium chloride solution only. Tenecteplase (TNK-tPA, Metalyse^®) is incompatible with dextrose solution. No other medicinal product should be added to the injection solution.

Tenecteplase (TNK-tPA, Metalyse^®) dosing scheme

Patient's body weight category (kg)	Tenecteplase (TNK-tPA, Metalyse®) (U)	Tenecteplase (TNK-tPA, Metalyse®) (mg)	Corresponding volume of reconstituted solution (mL)
<60	6000	30	6
≥60 to <70	7000	35	7
<60	6000	30	6
≥70 to < 80	8000	40	8
≥80 to < 90	9000	45	9
≥90	10000	50	10

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Tenecteplase (TNK-tPA, Metalyse^®) is supplied in a 20 mL glass vial type I, with a coated grey rubber stopper and a flip-off cap filled with powder for solution for injection.

Each vial of Tenecteplase (TNK-tPA, Metalyse^®) is packaged with a 10 mL plastic syringe pre-filled with 10 mL of sterile water for injections for reconstitution and a sterile vial adapter.

Tenecteplase (TNK-tPA, Metalyse^®) should not be stored above 30°C. The container should be kept in the outer carton. Each pack has a shelf life of 2 years.

Tenecteplase (TNK-tPA, Metalyse^®) should be reconstituted by adding the complete volume of water for injections from the pre-filled syringe to the vial containing the powder for injection, according to the following instructions (see Table):

Ensure that the appropriate vial size is chosen according to the body weight of the patient.
Ensure that the cap of the vial is intact.
Remove the flip-off cap from the vial.
Remove the tip-cap from the syringe. Then immediately screw the pre-filled syringe on the vial adapter and penetrate the vial stopper in the middle with the spike of the vial adapter.
Add the water for injections into the vial by pushing the syringe plunger down slowly to avoid foaming.
Reconstitute by swirling gently.
The reconstituted preparation results in a colourless to pale yellow, clear solution. Only clear solution without particles should be used.
Directly before the solution is to be administered, invert the vial with the syringe still attached, so that the syringe is below the vial.
Withdraw into the syringe the appropriate volume of reconstituted solution of Tenecteplase (TNK-tPA, Metalyse^®), based on the patient's weight.
Disconnect the syringe from the vial adapter.
Tenecteplase (TNK-tPA, Metalyse^®) is to be administered to the patient, intravenously in about 10 seconds. It should not be administered in a line containing dextrose.
Any unused solution should be discarded.

The reconstituted product has been shown to remain chemically and physically stable for up to 24 hours at 30°C. However, from a microbiological point of view, the product should be used immediately after reconstitution. If it is not used immediately, in-use storage times would normally not be longer than 24 hours at 2–8°C. Alternatively the reconstitution can be performed with the included needle.