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Crysvita (Subcutaneous)

Generic name: burosumab-twzabur-OH-sue-mab-- twza ]
Drug class: Miscellaneous metabolic agents

Medically reviewed by Last updated on Apr 3, 2023.

Uses for Crysvita

Burosumab-twza injection is used to treat X-linked hypophosphatemia (low phosphate levels in the blood). This medicine is also used to treat FGF23-related hypophosphatemia in patients with tumor-induced osteomalacia (soft bones) whose tumors are limited to a certain part of the body and cannot be removed by surgery.

This medicine should be given only by or under the direct supervision of your doctor.

Before using Crysvita

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Appropriate studies have not been performed on the relationship of age to the effects of burosumab-twza injection in children younger than 6 months of age with X-linked hypophosphatemia and in children younger than 2 years of age with FGF23-related hypophosphatemia. Safety and efficacy have not been established.


Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of burosumab-twza injection in the elderly. However, elderly patients are more likely to have age-related liver, kidney, or heart problems, which may require caution and an adjustment in the dose in patients receiving burosumab-twza.

Breast Feeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with Medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

  • Calcifediol
  • Calcitriol
  • Dihydrotachysterol
  • Doxercalciferol
  • Paricalcitol
  • Potassium Phosphate
  • Sodium Phosphate, Dibasic
  • Sodium Phosphate, Monobasic

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Kidney disease, severe (eg, end-stage kidney disease)—Should not be used in patients with this condition.
  • Restless leg syndrome—Use with caution. May make this condition worse.

Proper use of Crysvita

A nurse or other trained health professional will give you this medicine. It is given as a shot under the skin of your upper arms, thighs, buttocks, or stomach every 2 or 4 weeks.

Missed Dose

Call your doctor or pharmacist for instructions.

Precautions while using Crysvita

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.

You should not receive this medicine if your phosphate level is within or above the normal range for your age, or if you are using an oral phosphate or an active vitamin D analog (eg, calcifediol, calcitriol, doxercalciferol, paricalcitol).

This medicine may cause serious allergic reactions. These can be life-threatening and require immediate medical attention. Tell your doctor right away if you have fast heartbeat, fever, hives, itching, irritation, hoarseness, joint pain, stiffness, or swelling, rash, redness of the skin, swelling of the eyelids, face, lips, hands, or feet, tightness in the chest, or troubled breathing or swallowing after receiving this medicine.

This medicine may increase the phosphate level in your blood, which may increase your risk for nephrocalcinosis (high calcium level in the kidneys). This is more likely if you receive this medicine when your phosphate level is above the normal range. Talk to your doctor if you have any concerns.

Check with your doctor right away if you have bleeding, blistering, burning, coldness, discoloration of the skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site.

This medicine may cause or worsen existing restless leg syndrome. Check with your doctor right away if you have aching or discomfort in the lower legs or sensation of crawling in the legs.

Side Effects of Crysvita

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur:

More common

  • Bleeding, blistering, burning, coldness, discoloration of the skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site
  • bone malformations
  • confusion
  • cough or hoarseness
  • fast or irregular heartbeat
  • fever
  • frequent bone fractures
  • hives, itching, skin rash
  • irritation
  • joint pain, stiffness, or swelling
  • mood or mental changes
  • muscle cramps in the hands, arms, feet, legs, or face
  • numbness and tingling around the mouth, fingertips, or feet
  • pain in the arm or leg
  • redness of the skin
  • seizures
  • slowed growth
  • stomach cramps
  • swelling of the eyelids, face, lips, hands, or feet
  • tightness in the chest
  • tremor
  • troubled breathing or swallowing

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  • Aching or discomfort in the lower legs or sensation of crawling in the legs
  • back pain
  • constipation
  • diarrhea
  • difficulty with moving
  • dizziness
  • headache
  • muscle ache, pain, spasm, or stiffness
  • nausea
  • toothache
  • vomiting

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Frequently asked questions

Further information

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