July 1, 2016
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Atryn

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Atryn

Indications
Dosage
How Supplied

INDICATIONS

ATryn® is a recombinant antithrombin indicated for the prevention of peri-operative and peri-partum thromboembolic events in hereditary antithrombin deficient patients1.

It is not indicated for treatment of thromboembolic events in hereditary antithrombin deficient patients.

DOSAGE AND ADMINISTRATION

For Intravenous Use Only after Reconstitution

Preparation For Administration

  • Bring vials to room temperature no more than 3 hours prior to reconstitution.
  • For the 525 IU vial, reconstitute with 3.2 mL Sterile Water for Injection [(WFI) not supplied with ATryn] immediately prior to use. Do not shake.
  • For the 1750 IU vial, reconstitute with 10 mL Sterile Water for Injection [(WFI) not supplied with ATryn] immediately prior to use. Do not shake.
  • Do not use solution containing visible particulates or if it is discolored or cloudy.
  • Draw solution from one or more vials into a sterile disposable syringe for intravenous administration or add solution to an infusion bag containing 0.9% sterile sodium chloride for injection (e.g., dilute solution to obtain a concentration of 100 IU/mL).
  • Administer using an infusion set with a 0.22 micron poresize, in-line filter.
  • Administer contents of infusion syringes or diluted solution within 24 hours of preparation when stored at room temperature (68-77°F (20-25°C)).
  • Discard unused product in accordance with local requirements.

Recommended Dose And Schedule

  • The dosage of ATryn is to be individualized based on the patient's pre-treatment functional AT activity level (expressed in percent of normal) and body weight (expressed in kilograms) and using therapeutic drug monitoring (Table 1).
  • The goal of treatment is to restore and maintain functional antithrombin (AT) activity levels between 80% - 120% of normal (0.8 - 1.2 IU/mL).
  • Treatment should be initiated prior to delivery or approximately 24 hours prior to surgery to ensure that the plasma antithrombin level is in the target range at that time.
  • Different dosing formulae are used for the treatment of surgical and pregnant patients. Pregnant women who need a surgical procedure other than Cesarean section should be treated according to the dosing formulae for pregnant patients.
  • Administer loading dose as a 15-minute intravenous infusion, immediately followed by a continuous infusion of the maintenance dose.
  • AT activity monitoring and dose adjustments should be made according to Table 2.
  • Continue treatment until adequate follow-on anticoagulation is established.

Table 1: Dosing Formula for Surgical Patients and Pregnant Women

Surgical Patients
Loading Dose (IU) (100 – baseline AT activity level)/2.2 x Body Wt(kg)
Maintenance Dose (IU/hour) (100 – baseline AT activity level)/ 10.2 x Body Wt (kg)
Pregnant Women
Loading Dose (IU) (100 – baseline AT activity level)/1.3 x Body Wt (kg)
Maintenance Dose (IU/hour) (100 – baseline AT activity level)/ 5.4 x Body Wt (kg)
AT Activity Monitoring And Dose Adjustment

AT activity monitoring is required for proper treatment. Check AT activity once or twice per day with dose adjustments made according to Table 2.

Table 2: AT Activity Monitoring and Dose Adjustment

Initial Monitor Time AT Level Dose Adjustment Recheck AT Level
2 hours after initiation of treatment < 80% Increase 30% 2 hours after each dose adjustment
80% to 120% None 6 hours after initiation of treatment or dose adjustment
> 120% Decrease 30% 2 hours after each dose adjustment

As surgery or delivery may rapidly decrease the AT activity levels, check the AT level just after surgery or delivery. If AT activity level is below 80%, an additional bolus dose may be administered to rapidly restore decreased AT activity level. In such instances, the loading dose formulae in Table 1 should be used, utilizing in the calculation the last available AT activity result. Thereafter, restart the maintenance dose at the same rate of infusion as before the bolus.

HOW SUPPLIED

Dosage Forms And Strengths

ATryn is a sterile lyophilized formulation. Each vial of ATryn contains the potency stated on the label, which is approximately 525 IU or 1750 IU.

Dosage Form

ATryn 525 IU Vial - NDC 42976-121-01

Approximately 525 IU/vial in a sterile white to off-white lyophilized powder for reconstitution. Each carton contains one single dose vial of ATryn.

The actual potency of ATryn is stated on the vial label and carton.

ATryn 1750 IU Vial - NDC 42976-121-02

Approximately 1750 IU/vial in a sterile white to off-white lyophilized powder for reconstitution. Each carton contains one single dose vial of ATryn.

The actual potency of ATryn is stated on the vial label and carton.

Storage And Handling

Store ATryn refrigerated at between 2-8°C (36-46°F). Do not use product beyond the expiration date printed on the package. Discard unused portions.

REFERENCES

(1) Patnaik MM, Moll S. Inherited antithrombin deficiency: a review. Haemophilia 2008;14:1229-39.

Manufacturer: rEVO Biologics, Inc., Framingham, MA 01702, U.S.A. Revised: Dec 2013

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 5/25/2016

Indications
Dosage
How Supplied

Report Problems to the Food and Drug Administration

 

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.


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