Assess for signs/symptoms of hypophosphatasia (biochemical, medical history, and radiographic evidence of hypophosphatasia, as well as presence of any of the following: rachitic chest deformity, vitamin B6–dependent seizures, or failure to thrive) prior to therapy.
Monitor for signs/symptoms of hypersensitivity reactions (difficulty breathing, choking sensation, nausea, periorbital edema, dizziness, vomiting, fever, headache, flushing, irritability, chills, erythema, rash, pruritus, oral hypoesthesia). If reaction occurs, immediately discontinue, and start emergency treatment. Consider the risks and benefits of readministering following severe hypersensitivity reactions.
Assess for lipohypertrophy and injection site atrophy.
Obtain baseline ophthalmalogic exams and renal ultrasounds periodically during therapy to monitor for calcifications leading to visual changes and decreased renal function.
Lab Test Considerations:
Inform lab that asfotase alfa interferes with alkaline phosphatase testing. High serum alkaline phosphatase levels are expected and reflect circulating concentrations of asfotase alfa. Do not use alkaline phosphatase levels for clinical decisions.
Administer in a health care setting with appropriate medical monitoring and supportive measures (cardiopulmonary resuscitation equipment) available during administration.
SUBQ Remove from the refrigerator 15–30 min before injecting to allow the liquid to reach room temperature (do not warm any other way). Prepare dose using 1 mL syringes and ½-inch needles, 25–29 gauge. See manufacturer's guidelines for dose preparation. If >1 mL, split volume equally between two syringes, and administer two injections in two separate sites. Solution is clear, colorless to slightly yellow, opalescent or slightly opalescent, with few translucent or white particles. Discard any vial(s) not consistent with this appearance. Do not shake vials. Remove air bubbles from syringe. Pinch skin and inject at 90° angle; for patients with little fat, use 45° angle. Rotate sites between abdomen, upper arms, and upper legs to prevent lipodystrophy. Do not inject into areas that are hot, red, or swollen. Administer within 3 hr upon removal of the vial(s) from refrigeration; do not freeze. Vials are one time use only. Discard any unused product. Protect from light.
Explain purpose and side effects of medication to patient. Advise patient to read Patient Information before starting therapy.
Advise patient to notify health care provider of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care provider before taking other medications.
Instruct patient and/or caregiver if a dose is missed, take as soon as remembered. If it is close to the time of the next dose, skip the missed dose and go back to the normal time. Do not give simultaneous double or extra doses.
Teach patient and/or caregiver the signs/symptoms of an hypersensitivity reaction; if any occur, seek immediate medical care.
Advise patients and/or caregiver to monitor for skin thickening or pits at injection sites. Rotate injection sites to prevent lipodystrophy.
Explain need for eye and kidney exams periodically during therapy to patient and/or caregiver.
Encourage patient and/or caregiver to enroll patient in the Hypophosphatasia Registry to better understand hypophosphatasia and monitor long-term progress of patients. Participation is voluntary at www.hppregistry.com.
Rep: Advise women of reproductive potential to notify health care professional if pregnancy is planned or suspected or if breastfeeding.