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Strensiq

Generic Name: asfotase alfa (AS foe tase AL fa)
Brand Names: Strensiq

Medically reviewed by P. Thornton, DipPharm Last updated on Feb 5, 2019.

What is Strensiq?

Strensiq (asfotase alfa) is an enzyme replacement medicine that is used to treat hypophosphatasia (HYE-poe-FOS-fa-TAY-zha).

Hypophosphatasia is a rare genetic disorder in which there is a deficiency of an enzyme that helps the body process calcium and phosphorus. This leads to abnormal growth and development of the bones and teeth, including soft or brittle bones, growth problems, and tooth loss.

Strensiq may also be used for purposes not listed in this medication guide.

Important Information

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Before taking this medicine

You should not use Strensiq if you are allergic to asfotase alfa.

Before you use Strensiq, tell your doctor about all your medical conditions or allergies.

Your name may be listed on a patient registry while you are using Strensiq. This is to track and evaluate any long-term effects of using this medicine.

It is not known whether Strensiq will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It is not known whether asfotase alfa passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

How should I use Strensiq?

Strensiq is usually given 3 to 6 times per week. Follow your doctor's dosing instructions very carefully. Do not use this medicine in larger or smaller amounts or for longer than recommended.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Strensiq is injected under the skin. A healthcare provider may teach you how to properly use the medication by yourself.

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you don't understand all instructions.

Prepare an injection only when you are ready to give it. Do not use if the medicine has changed colors or has particles in it. Call your pharmacist for new medicine.

You may need to use 2 vials and 2 separate syringes to make up a single dose of this medicine. Follow your doctor's dosing instructions very carefully.

Your care provider will show you where to on your body to inject Strensiq. Use a different place each time you give an injection. Do not inject into the same place two times in a row.

Strensiq doses are based on weight (especially in children and teenagers). Your dose needs may change if you gain or lose weight.

You may need frequent eye examinations.

This medicine can affect the results of certain medical tests. Tell any doctor who treats you that you are using Strensiq.

Store this medicine in the original container in a refrigerator, protected from light. Do not freeze or shake this medicine.

You may take the medicine out of the refrigerator and let it reach room temperature before injecting your dose. Do not leave the medicine out for longer than 1 hour.

Each vial (bottle) is for one use only. Throw it away after one use, even if there is still medicine left inside.

Use a needle and syringe only once and then place them in a puncture-proof "sharps" container. Follow state or local laws about how to dispose of this container. Keep it out of the reach of children and pets.

Strensiq dosing information

Usual Adult Dose of Strensiq for Hypophosphatasia:

Usual dose: 2 mg/kg subcutaneously 3 times per week OR 1 mg/kg subcutaneously 6 times per week
Maximum dose: 9 mg/kg per week

Comments:
-For patients with perinatal/infantile-onset hypophosphatasia (HPP), an increase to 3 mg/kg three times per week may be necessary for insufficient efficacy (e.g., no improvement in respiratory status, growth, or radiographic findings).
-Injection site reactions may limit the tolerability of the 6 times per week dosing regimens.

Use: For the treatment of patients with perinatal/infantile and juvenile onset HPP.

Usual Pediatric Dose of Strensiq for Hypophosphatasia:

Usual dose: 2 mg/kg subcutaneously 3 times per week OR 1 mg/kg subcutaneously 6 times per week
Maximum dose: 9 mg/kg per week

Comments:
-For patients with perinatal/infantile-onset hypophosphatasia (HPP), an increase to 3 mg/kg three times per week may be necessary for insufficient efficacy (e.g., no improvement in respiratory status, growth, or radiographic findings).
-Injection site reactions may limit the tolerability of the 6 times per week dosing regimens.

Use: For the treatment of patients with perinatal/infantile and juvenile onset HPP.

What happens if I miss a dose?

Call your doctor for instructions if you miss a dose of Strensiq.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using Strensiq?

Do not inject this medicine into skin areas that are red or swollen.

Strensiq side effects

Get emergency medical help if you have signs of an allergic reaction to Strensiq: hives; dizziness, nausea, vomiting; difficult breathing, choking sensation; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • vision changes;

  • urinating more or less than usual;

  • painful or difficult urination;

  • pink, red, or brown urine; or

  • severe pain in your side or lower back.

Common Strensiq side effects may include:

  • pain, itching, swelling, redness, bruising, hardening, pitting, or other skin changes where the medicine was injected.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Strensiq?

Other drugs may interact with asfotase alfa, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Strensiq only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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