Stay Connected

Strensiq® (asfotase alfa) Dosing

How is Strensiq® given?

  • Strensiq is given as an injection under the skin (called a subcutaneous injection)
  • Depending on a person’s age and ability, Strensiq can be self-injected or injected by a caregiver
  • Always use Strensiq exactly as your healthcare provider tells you
  • Speak with your doctor about how much Strensiq to use and when to use it

How is Strensiq® dosed?

Strensiq is dosed in milligrams based on weight. Strensiq is available as either 1 mg per kg of body weight, 6 times per week, or 2 mg per kg of body weight, 3 times per week. Your doctor will decide which dosage is right for you.

If needed, the dose may be increased to 9 mg/kg, 3 times per week, for children with perinatal/infantile-onset hypophosphatasia.

If there have been any significant changes in weight for you or your child, your doctor will adjust the dosage.

It is important to use Strensiq as described in the Patient Prescribing Information and Instructions for Use , or as instructed by your doctor, nurse, or pharmacist.

Learn how to inject Strensiq® (asfotase alfa)

Get tips and step-by-step instructions.

Learn about the services available to you through the OneSource Program.

Call 1-888-765-4747 to enroll and be matched with an Alexion nurse case manager!



Strensiq is a prescription medicine used to treat people with perinatal/infantile- and juvenile-onset hypophosphatasia (HPP).

What are the possible side effects of STRENSIQ?
STRENSIQ may cause serious side effects, including
  • Serious allergic (hypersensitivity) reactions happened in some people who use STRENSIQ. Stop using STRENSIQ and go to the nearest hospital emergency room right away if you or your loved one have any of the signs and symptoms of a serious allergic reaction, including
    • Difficulty breathing
    • Swelling of your eyes, lips, or tongue
    • Hives
    • Feeling faint
    • Nausea or vomiting
    • Dizziness
    • Itching of your lips, tongue, or throat
    • Choking sensation
  • Skin thickening or pits at the injection site (lipodystrophy) has happened several months after using STRENSIQ.
  • Calcium buildup in the eyes and kidneys can occur if you or your loved one have HPP. Your healthcare provider should check the eyes and kidneys while you or your loved one use STRENSIQ.
  • Decreased efficacy. Contact your healthcare provider if you or your loved one notice STRENSIQ is no longer working or experience worsening symptoms of HPP (e.g., increased respiratory support, increased difficulty walking, new fractures).
The most common side effects of STRENSIQ include local skin injection-site reactions (including red skin patches, bruising, color change, pain, itching, thinning, swelling, pits, and bumps) and calcium buildup in your eyes and kidneys.

Strensiq may affect other lab test results, therefore it is important that you present your Medical Alert Card to your healthcare team so they are aware that you are being treated with an alkaline phosphatase (ALP) replacement therapy which may cause incorrect results on certain laboratory tests.

 Tell your doctor if you are pregnant or plan to become pregnant, or are breastfeeding or plan to breastfeed.

These are not all the possible side effects of STRENSIQ. For more information, ask your healthcare provider or pharmacist. Call your healthcare provider for medical advice about side effects. You may report side effects to the US Food and Drug Administration at 1-800-FDA-1088.

Please see STRENSIQ full Prescribing Information, including Patient Information and Instructions for Use.