TNKase

tenecteplase

Metalyse, TNKase

Pharmacologic class: Tissue plasminogen activator

Therapeutic class: Thrombolytic enzyme

Pregnancy risk category C

Action

Binds to fibrin and converts plasminogen to plasmin, which breaks down fibrin clots and lyses thrombi and emboli. Causes systemic fibrinolysis.

Availability

Powder for injection: 50 mg/vial with 10-ml syringe and TwinPak Dual Cannula Device and 10-ml vial of sterile water for injection

Indications and dosages

➣ To reduce mortality associated with acute myocardial infarction

Adults weighing 90 kg (198 lb) or more: 50 mg I.V. bolus given over 5 seconds

Adults weighing 80 kg to 89 kg (176 to 197 lb): 45 mg I.V. bolus given over 5 seconds

Adults weighing 70 kg to 79 kg (154 to 175 lb): 40 mg I.V. bolus given over 5 seconds

Adults weighing 60 to 69 kg (132 to 153 lb): 35 mg I.V. bolus given over 5 seconds

Adults weighing less than 60 kg (132 lb): 30 mg I.V. bolus given over 5 seconds

Contraindications

• Hypersensitivity to drug or other tissue plasminogen activators

• Active internal bleeding

• Bleeding diathesis

• Recent intracranial or intraspinal surgery or trauma

• Severe uncontrolled hypertension

• Intracranial neoplasm

• Arteriovenous malformation or aneurysm

• History of cerebrovascular accident (CVA)

Precautions

Use cautiously in:

• previous puncture of noncompressible vessels, organ biopsy, hypertension, acute pericarditis, high risk of left ventricular thrombosis, subacute bacterial endocarditis, hemostatic defects, diabetic hemorrhagic retinopathy, septic thrombophlebitis, obstetric delivery

• patients taking warfarin concurrently

• patients older than age 75

• pregnant or breastfeeding patients.

Administration

• Reconstitute by mixing contents of prefilled syringe with 10 ml of sterile water for injection. Swirl gently; don't shake. Draw up prescribed dosage from vial, then discard remainder. Give I.V. over 5 seconds through designated line.

Don't deliver in same I.V. line with dextrose solutions. Flush I.V. line with normal saline solution before giving drug if patient has been receiving dextrose.

Give with heparin if ordered, but not through same I.V. line.

Adverse reactions

CNS: intracranial hemorrhage, CVA

CV: hypotension, arrhythmia, myocardial rupture, myocardial reinfarction, cardiogenic shock, atrioventricular block, cardiac arrest, cardiac tamponade, heart failure, pericarditis, pericardial effusion, mitral regurgitation, thrombosis, embolism, hemorrhage

EENT: epistaxis, minor pharyngeal bleeding

GI: nausea, vomiting, hemorrhage

GU: hematuria

Hematologic: anemia, bleeding tendency

Respiratory: respiratory depression, pulmonary edema, apnea

Skin: bleeding at puncture sites, hematoma

Interactions

Drug-drug. Anticoagulants, aspirin, dipyridamole, indomethacin, phenylbutazone: increased bleeding risk

Drug-diagnostic tests. Coagulation tests: fibrinogen degradation in blood sample

Patient monitoring

Monitor ECG. Stay alert for reperfusion arrhythmias.

Monitor vital signs carefully. Watch for signs and symptoms of respiratory depression and reinfarction.

Evaluate all body systems closely for signs and symptoms of bleeding. If bleeding occurs, stop drug and give antiplatelet agents, as ordered.

• Monitor CBC and coagulation studies. However, know that drug may skew coagulation results.

Patient teaching

Inform patient that drug increases risk of bleeding. Advise him to immediately report signs and symptoms of bleeding.

• Teach patient safety measures to avoid bruising and bleeding.

• Tell patient he'll undergo regular blood tests during therapy.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.

tenecteplase

(te-nek-te-plase) tenecteplase,

TNKase

(trade name)

Classification

Therapeutic: thrombolytics
Pharmacologic: plasminogen activators
Pregnancy Category: C

Indications

Reduction of mortality associated with acute myocardial infarction.

Action

Converts plasminogen to plasmin, which is then able to degrade fibrin present in clots. Directly activates plasminogen.

Therapeutic effects

Lysis of thrombi in coronary arteries, with preservation of myocardium and resultant decrease in mortality.

Pharmacokinetics

Absorption: IV administration results in complete bioavailability.Distribution: Unknown.Metabolism and Excretion: Mostly metabolized by the liver.Half-life: Initial phase—20–24 min; terminal phase— 90–130 min.

Time/action profile (fibrinolysis)

ROUTEONSETPEAKDURATION
IVrapidunknownunknown

Contraindications/Precautions

Contraindicated in: Active internal bleeding; History of cerebrovascular accident; Recent (within 2 mo) intracranial or intraspinal surgery or trauma; Intracranial neoplasm, arteriovenous malformation, or aneurysm; Severe uncontrolled hypertension; Known bleeding diathesis; Hypersensitivity.Use Cautiously in: Recent major surgery, trauma, GI, or GU bleeding; Cerebrovacular disease; Hypertension (BP ≥180 mm Hg and or diastolic ≥110 mm Hg); Presence or high likelihood of left heart thrombus; Subacute bacterial endocarditis or acute pericarditis; Hemostatic defect especially those associated with severe hepatic or renal disease; Severe hepatic dysfunction; Geriatric patients (increased risk of intracranial bleeding); Hemorrhagic ophthalmic conditions; Septic phlebitis or occulded AV cannula at infected site; Concurrent warfarin therapy or recent therapy with glycoptrotein (GP) IIb/IIIa inhibitors (abciximab, eptifibatide, tirofiban); Pregnancy, lactation, or children (safety not established).

Adverse Reactions/Side Effects

Adverse reactions are frequently sequelae of underlying disease

Cardiovascular

  • arrthythmias (life-threatening)
  • cardiogenic shock (life-threatening)
  • cardiac tamponade
  • embolism (life-threatening)
  • heart failure (life-threatening)
  • myocardial infarction (life-threatening)
  • myocardial rupture (life-threatening)
  • pericarditis (life-threatening)
  • pericardial effusion (life-threatening)
  • pulmonary edema (life-threatening)
  • recurrent myocardial ischemia (life-threatening)
  • thrombosis (life-threatening)
  • hypotension

Gastrointestinal

  • nausea
  • vomiting

Hematologic

  • bleeding (life-threatening)

Miscellaneous

  • allergic reactions including anaphylaxis
  • fever

Interactions

Drug-Drug interaction

Aspirin, NSAIDs, warfarin, heparin and heparin-like agents, abciximab, eptifibatide, tirofiban, clopidogrel, ticlopidine, or dipyridamole —concurrent use may increase the risk of bleeding, although these agents are frequently used together or in sequence.Risk of bleeding may be increased by concurrent use of cefotetan, cefoperazone, or valproic acid.

Route/Dosage

Intravenous (Adults <60 kg) 30 mg.Intravenous (Adults ≥60 kg and <70 kg) 35 mg.Intravenous (Adults ≥70 kg and <80 kg) 40 mg.Intravenous (Adults ≥80 kg and <90 kg) 45 mg.Intravenous (Adults ≥90 kg) 50 mg.

Availability

Powder for injection: 50 mg/vial with 10 mL syringe and TwinPak Dual Cannula Device, and 10 mL vial of sterile water for injection

Nursing implications

Nursing assessment

  • Begin therapy as soon as possible after the onset of symptoms.
    • Assess patients for bleeding every 15 min during the 1st hr, every 15–30 min during the next 8 hr and at least every 4 hr for the duration of therapy. Frank bleeding may occur from invasive sites or body orifices. Internal bleeding may also occur (decreased neurologic status, abdominal pain with coffee-ground emesis or black tarry stools, joint pain). If uncontrolled bleeding occurs, stop tenecteplase immediately.
    • Monitor vital signs, including temperature, every 4 hr during course of therapy. Do not use lower extremities to measure BP. Notify health care professional if systolic BP >180 mmHg or diastolic BP >110 mmHg. Tenecteplase should not be given if hypertension is uncontrolled. Inform health care professional if hypotension occurs. Hypotension may result from the drug, hemorrhage, or cardiogenic shock.
    • Assess neurologic status throughout therapy. Altered sensorium or mental changes may be indicative of intracranial bleeding.
  • Coronary Thrombosis:: Monitor ECG continuously in patients with coronary thrombosis for significant arrhythmias. Antiarrhythmics may be ordered prior to or during alteplase therapy to prevent reperfusion arrhythmias. Cardiac enzymes should be monitored. Coronary angiography or radionuclide myocardial scanning may be used to assess effectiveness of therapy.
    • Assess intensity, character, location, and radiation of chest pain. Note presence of associated symptoms (nausea, vomiting, diaphoresis). Administer analgesics as ordered by physician. Notify health care professional if chest pain is unrelieved or recurs.
    • Monitor heart and breath sounds frequently. Inform health care professional of signs of HF (rales/crackles, dyspnea, S3 heart sound, jugular venous distention, elevated CVP).
  • Lab Test Considerations: Monitor hematocrit, hemoglobin, platelet count, prothrombin time, thrombin time, activated partial thromboplastin time, and fibrinolytic activity prior to and frequently throughout therapy. Bleeding time may be assessed prior to therapy if patient has received platelet aggregation inhibitors.
    • Obtain type and crossmatch of blood and have blood available at all times in case of hemorrhage.
    • Stools should be tested for occult blood loss and urine tested for hematuria periodically during therapy.
    • If local bleeding occurs, apply pressure to site. If severe internal bleeding occurs, discontinue infusion. Clotting factors and/or blood volume may be restored through infusions of whole blood, packed RBCs, fresh frozen plasma, or cryoprecipitate. Do not administer dextran, as it has antiplatelet activity. Aminocaproic acid (Amicar) may be used as an antidote.

Potential Nursing Diagnoses

Acute pain
Ineffective tissue perfusion (Indications)
Risk for injury, high risk for (Adverse Reactions)

Implementation

  • high alert: Overdosage and under-dosage of thrombolytic medications have resulted in patient harm and/or death. Have second practitioner independently check original order, dosage calculations, and infusion pump settings. Do not confuse the abbreviation t-PA for alteplase (Activase) with the abbreviation TNK t-PA for tenecteplase (TNKase). Clarify orders that contain either of these abbreviations.
  • Tenecteplase should be used only in settings where hematologic function and clinical response can be adequately monitored. Avoid IM injections and unnecessary venipunctures. Apply pressure to all arterial and venous punctures for at least 30 min. Avoid venipunctures at noncompressible sites (e.g., jugular and subclavian sites).
    • Avoid invasive procedures, such as IM injections or arterial punctures, with this therapy. If such procedures must be performed, apply pressure to all arterial and venous puncture sites for at least 30 min. Avoid venipunctures at noncompressible sites (jugular vein, subclavian site).
    • Systemic anticoagulation with heparin is usually begun several hours after the completion of thrombolytic therapy.
    • Acetaminophen may be ordered to control fever.
  • Intravenous Administration
  • pH: 7.3.
  • Intravenous: Prior to therapy start two IV lines: one for tenecteplase, the other for any additional IV infusions.
  • Intermittent Infusion: Diluent: Vials are packaged with sterile water for injection (without preservatives) to be used as diluent. Do not use bacteriostatic water for injection. Do not discard shield assembly. To reconstitute aseptically withdraw 10 mL of diluent and inject into the tenectplase vial, directing the stream into the powder. Slight foaming may occur; large bubbles will dissipate if left standing undisturbed for several minutes. Swirl gently until contents are completely dissolved; do not shake. Solution containing 5 mg/mL is clear and colorless to pale yellow. Withdraw dose from reconstituted vial with the syringe and discard unused portion. Once dose is in syringe, stand the shield vertically on a flat surface (with green side down) and passively recap the red hub cannula. Remove the entire shield assembly, including the red hub cannula, by twisting counter clockwise. Shield assembly also contains the clear-ended blunt plastic cannula; retain for split septum IV access. Reconstitute immediately before use. May be refrigerated and administered within 8 hrs.
  • Rate: Administer as a single IV bolus over 5 seconds.
  • Y-Site Incompatibility: Precipitate forms in line when administered with dextrose-containing solutions. Flush line with saline-containing solution prior to and following administration of tenecteplase.
  • Additive Incompatibility: Do not admix.

Patient/Family Teaching

  • Explain to patient and family the purpose of tenecteplase and the need for close monitoring.
  • Advise patient to remain on bed rest and to avoid unnecessary procedures such as shaving and vigorous toothbrushing for 24 hr.
  • Instruct patient to report signs of hypersensitivity and bleeding promptly.

Evaluation/Desired Outcomes

  • Restoration of coronary perfusion resulting in limitation of infarct size and decrease in complications, such as mortality.

TNKase®

Tenecteplase, see there.