Asfotase alfa

Generic name: asfotase alfa [ AS-foe-tase-AL-fa ]
Brand name: Strensiq
Dosage form: subcutaneous solution (18 mg/0.45 mL; 28 mg/0.7 mL; 40 mg/mL; 80 mg/0.8 mL)
Drug class: Miscellaneous metabolic agents

Medically reviewed by Drugs.com on Jul 5, 2023. Written by Cerner Multum.

What is asfotase alfa?

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.

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

Asfotase alfa side effects

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

Asfotase alfa may cause serious side effects. 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 side effects of asfotase alfa 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.

Related/similar drugs

Strensiq

Warnings

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

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

Tell your doctor if you are pregnant or breast-feeding.

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

How should I use asfotase alfa?

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

Asfotase alfa is usually given 3 to 6 times per week. Follow your doctor's dosing instructions very carefully.

Asfotase alfa 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 on your body to inject asfotase alfa. Use a different place each time you give an injection. Do not inject into the same place two times in a row.

Asfotase alfa 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 asfotase alfa.

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.

Asfotase alfa dosing information

Usual Adult Dose for Hypophosphatasia:

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 for Hypophosphatasia:

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).
-For patients weighing less than 40 kg: Do not use the 80 mg/0.8 mL vial because the systemic exposure is lower than that achieved with the lower strength vials and may not be adequate for these patients.
-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 asfotase alfa.

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 asfotase alfa?

Do not inject asfotase alfa into skin areas that are red or swollen.

What other drugs will affect asfotase alfa?

Other drugs may affect 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 this medication only for the indication prescribed.

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

Medical Disclaimer

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