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Generic name: pegvaliasepeg-VAL-i-ase ]
Drug class: Miscellaneous metabolic agents

Medically reviewed by on Jun 1, 2023. Written by Cerner Multum.

What is Palynziq?

Palynziq is used to lower phenylalanine blood levels in adults with phenylketonuria (PKU) not controlled with other treatment.

Palynziq is available only from a certified pharmacy under a special program.

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

Palynziq side effects

Stop the Palynziq injection and get emergency medical help if you have signs of an allergic reaction:

Common side effects of Palynziq may include:

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.


Palynziq can cause a serious allergic reaction. Your first dose will be given in a medical setting.

Get emergency medical help if you have signs of an allergic reaction such as hives, itching, dizziness, wheezing, trouble breathing, or swelling in your face or throat. Your doctor may prescribe an epinephrine injection kit to keep with you at all times.

Before taking this medicine

Palynziq can cause a serious allergic reaction. Your doctor may prescribe an epinephrine injection kit to use in case you have a severe allergic reaction. Keep this injection kit with you at all times.

Tell your doctor if you think you might be unable to give yourself an emergency epinephrine injection.

Follow your doctor's instructions about using Palynziq if you are pregnant. Controlling your phenylalanine levels is very important during pregnancy. Your name may be listed on a pregnancy registry to track the effects of pegvaliase on the baby.

Ask a doctor if it is safe to breastfeed while using this medicine.

Not approved for use by anyone younger than 18 years old.

How should I use Palynziq?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Palynziq is injected under the skin. You may be given other medications to help prevent serious side effects or an allergic reaction.

You will receive your first dose in a medical setting to make sure you do not have an allergic reaction.

Read and follow all Instructions for Use. Ask your doctor or pharmacist if you need help.

Prepare an injection only when you are ready to give it. Call your pharmacist if the medicine looks cloudy, has changed colors, or has particles in it.

Do not shake the prefilled syringe or you may ruin the medicine.

Your healthcare provider will show you where to inject Palynziq. Do not inject into the same place two times in a row.

You may need to have someone with you for at least 1 hour after you inject this medicine at home, to watch you for signs of an allergic reaction and give the epinephrine injection if needed.

Read the Warning Card about allergic reactions and learn what symptoms to watch for. Keep the card with you at all times.

You will need frequent medical tests.

You will need to follow a special diet. Follow all instructions of your doctor or dietitian. Learn about the foods you should eat or avoid.

Store this medicine in the refrigerator, do not freeze.

You may store the medicine for up to 30 days at room temperature in its original container, protected from light. Do not put the medicine back into the refrigerator. Throw away any unused medicine after 30 days or after the expiration date on the label has passed.

Throw away a prefilled syringe after one use, even if there is still medicine left inside.

Do not reuse a needle or syringe. Place them in a puncture-proof "sharps" container and dispose of it following state or local laws. Keep out of the reach of children and pets.

What happens if I miss a dose?

Skip the missed dose and use your next dose at the regular time. Do not use two doses at one time.

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 Palynziq?

Avoid injecting into skin that is red, bruised, hard, tender, injured, or irritated. Do not inject Palynziq into skin areas with moles, scars, birthmarks, or tattoos.

What other drugs will affect Palynziq?

Other drugs may affect Palynziq, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use.

Frequently asked questions

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.