Why is this medication prescribed?

Crysvita (burosumab) is a medication prescribed for the treatment of X-linked hypophosphatemia (XLH), a genetic disorder that causes low levels of phosphate in the blood due to increased phosphate loss through the kidneys. This condition leads to weakened bones and other related symptoms. Crysvita works by inhibiting a protein called fibroblast growth factor 23 (FGF23), which helps to regulate phosphate levels and its reabsorption in the kidneys. By targeting this protein, Crysvita helps increase phosphate levels in the blood and improve bone health.

How should this medicine be used?

Crysvita (burosumab) is a medication used to treat X-linked hypophosphatemia (XLH), a genetic disorder that affects phosphate metabolism. Here are the general guidelines for its use:

• Dosage: The dosage of Crysvita is typically based on body weight and administered subcutaneously (under the skin). Your healthcare provider will determine the appropriate dose for you based on your weight and the severity of your condition.
• Administration: Crysvita is usually injected under the skin once every two weeks. The injections can be given at a healthcare provider’s office or, in some cases, patients can be taught how to self-administer the injections at home.
• Monitoring: Regular monitoring of phosphate levels, renal function, and other relevant parameters may be necessary during treatment to ensure the medication is working effectively and to adjust the dose if needed.
• Compliance: It’s important to adhere to the dosing schedule prescribed by your healthcare provider to get the maximum benefit from Crysvita.
• Lifestyle considerations: Your healthcare provider may also recommend dietary adjustments or supplements to optimize the management of XLH alongside Crysvita.

As with any medication, it’s essential to follow your healthcare provider’s instructions carefully and report any concerns or side effects promptly. They can provide personalized guidance based on your specific health needs.

Other uses for this medicine

• Crysvita is primarily approved for the treatment of X-linked hypophosphatemia (XLH). There is limited evidence for other uses, and any off-label use should be discussed with your healthcare provider.
• Research and clinical trials may explore additional indications, but such uses would require approval and should be based on a healthcare provider’s recommendation and supervision.

What special precautions should I follow?

When using Crysvita, several special precautions should be followed:

• Allergic Reactions: Be aware of the signs of an allergic reaction, which can include rash, itching, swelling, severe dizziness, or trouble breathing. Seek immediate medical attention if any of these symptoms occur.
• Kidney Function: Crysvita can affect kidney function, so it’s important to monitor kidney function regularly during treatment. Patients with pre-existing kidney issues should be closely monitored.
• Phosphate Levels: Regular monitoring of blood phosphate levels is essential. Crysvita treatment aims to normalize these levels, and frequent blood tests will help ensure they remain within the target range.
• Injection Site Reactions: Injection site reactions such as pain, redness, or swelling may occur. Follow proper injection techniques and rotate injection sites to minimize these reactions.
• Pregnancy and Breastfeeding: If you are pregnant, plan to become pregnant, or are breastfeeding, discuss this with your healthcare provider. The safety of Crysvita during pregnancy and breastfeeding is not well established, and it should only be used if the benefits outweigh the risks.
• Interactions with Other Medications: Inform your healthcare provider of all other medications you are taking, including over-the-counter drugs, supplements, and herbal products. Although Crysvita is not known to have significant drug interactions, it’s crucial to consider all possible interactions.
• Bone Health Monitoring: Continuous monitoring of bone health and growth is important, especially in pediatric patients. Adjustments to treatment or additional therapies might be needed based on bone health evaluations.
• Patient Training: Ensure that patients or caregivers are properly trained in the administration of Crysvita if self-injection is planned. Incorrect administration can lead to decreased efficacy or increased risk of side effects.
• Medical History: Provide your healthcare provider with a full medical history, including any history of bone diseases or disorders, as this information can influence treatment decisions.

Always consult with a healthcare provider for personalized advice and to address any specific concerns or questions related to Crysvita and its use.

What special dietary instructions should I follow?

There are no specific dietary restrictions associated with Crysvita. However, maintaining a well-balanced diet is crucial for overall health, especially when managing a condition like X-linked hypophosphatemia.

What should I do if I forget a dose?

• Timing: If you miss a dose of Crysvita, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose—do not double up to make up for the missed dose.
• Guidance: Contact your healthcare provider for specific instructions if you miss a dose. They can provide guidance on how to proceed and whether any adjustments are needed
• Tracking: Keep a record of missed doses and communicate with your healthcare provider during follow-up visits to ensure your treatment plan remains effective.

What side effects can this medication cause?

Crysvita (burosumab) is a medication used to treat X-linked hypophosphatemia (XLH), a genetic disorder that affects phosphate metabolism. Like any medication, Crysvita can potentially cause side effects. Some of the common side effects include:

• Injection site reactions: Pain, swelling, or redness at the injection site.
• Headache: Some patients may experience headaches after taking Crysvita.
• Nausea: Feeling nauseous or having an upset stomach.
• Toothache: Dental problems such as toothache have been reported.
• Muscle pain: Pain or discomfort in muscles.
• Dizziness: Feeling lightheaded or dizzy.

These side effects are usually mild to moderate and tend to improve over time as the body adjusts to the medication. However, it’s important for patients to discuss any concerns or unusual symptoms with their healthcare provider. Additionally, there may be other less common or more serious side effects associated with Crysvita, so it’s essential to follow medical guidance closely when using this medication.

What should I know about storage and disposal of this medication?

Storage and Disposal:

• Storage:
  • Crysvita should be stored in a refrigerator at 36°F to 46°F (2°C to 8°C).
  • Do not freeze the medication. If accidentally frozen, it should not be used.
  • Keep Crysvita in its original carton to protect it from light.
  • Do not shake or agitate the vial.
• Disposal:
  • Dispose of Crysvita according to local regulations for hazardous waste. Do not throw it away in household trash or flush it down the toilet.
  • If you have unused or expired Crysvita, consult with your pharmacist or local waste disposal service for proper disposal methods.

In case of emergency/overdose

• Emergency Situations: If you suspect an allergic reaction or severe side effects (such as severe rash, difficulty breathing, or swelling of the face/lips/tongue), seek emergency medical help immediately.
• Overdose: If an overdose is suspected, contact Poison Control or go to the nearest emergency room right away. Provide information about the amount of Crysvita taken and the time of ingestion if possible.

What other information should I know?

• Dosage and Administration: Crysvita is typically administered as an injection under the skin (subcutaneously). Your healthcare provider will instruct you on the correct dosage and administration schedule. Do not self-administer Crysvita without proper training and guidance from a healthcare professional.
• Monitoring: Regular monitoring of phosphate levels and other relevant tests is necessary to ensure the effectiveness and safety of the treatment. Follow your healthcare provider’s recommendations for follow-up visits and lab tests.
• Interactions: Inform your healthcare provider about all other medications and supplements you are taking, as Crysvita may interact with other drugs.
• Side Effects: Be aware of potential side effects, which may include pain at the injection site, headache, or changes in phosphate levels. Report any unusual or severe side effects to your healthcare provider.
• Pregnancy and Nursing: If you are pregnant, planning to become pregnant, or breastfeeding, discuss the risks and benefits of Crysvita with your healthcare provider.

Always follow your healthcare provider’s instructions and consult them if you have any questions or concerns about Crysvita. They can provide you with personalized guidance based on your specific condition and treatment plan.