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PKU Basics

Understanding PKU

Phenylketonuria (PKU) is a genetic condition requiring lifelong management. Although PKU is a serious condition, there are steps you or your loved one can take to help maintain a healthy, productive life.

In someone with PKU, the phenylalanine hydroxylase (PAH) enzyme is either missing or not working properly, which can cause a buildup of phenylalanine (Phe) in the blood. High and/or unstable blood Phe levels can cause problems in the way you think, feel, and act.

Learn more about PKU

Symptoms of PKU

Symptoms of PKU can range from mild to severe and are the result of high or unstable blood Phe levels.

In children, symptoms may include:

  • Being cranky or fretful
  • Inability to focus
  • Anxiety
  • Severe intellectual disability (if left untreated)

In adults, symptoms may include:

  • Headache
  • Forgetfulness
  • Fatigue
  • Trouble focusing
  • Depression
  • Anxiety
  • Irritability
  • Isolation
  • Feeling “foggy”

Learn more about PKU signs and symptoms

Maintaining a Healthy, Productive Life With PKU

You can effectively manage PKU by1:

  • Starting treatment at birth and continuing for life
  • Controlling blood Phe levels every day

KUVAN® (sapropterin dihydrochloride) Tablets or Powder for Oral Solution is the first prescription medication for PKU. Experts recommend that everyone with PKU be offered a trial of KUVAN to determine if it can help lower blood Phe levels.1,*

Sign up for the FREE trial of KUVAN for up to 30 days

Your clinic team is dedicated to helping you manage your PKU. Talk with your clinic team to find out if KUVAN is right for you. Find a PKU clinic near you

Are you an adult with PKU with Phe levels above 600 micromol/L (10 mg/dL)?
Learn about another treatment option here

*Except those with two null mutations in trans.

Connect With the PKU Community

Discover an online community offering educational information, recipes, and other resources to people living with PKU.


Reference

  1. Vockley J, Andersson HC, Antshel KM, et al; for the American College of Medical Genetics and Genomics Therapeutic Committee. Phenylalanine hydroxylase deficiency: diagnosis and management guideline. Genet Med. 2014;16(2):188-200. doi:10.1038/gim.2013.157.

What is KUVAN?

KUVAN® (sapropterin dihydrochloride) Tablets for Oral Use and Powder for Oral Solution are prescription medicines used to lower blood Phe levels in adults and children over one month of age with a certain type of Phenylketonuria (PKU). KUVAN is to be used along with a Phe-restricted diet.

What is the most important information I should know about KUVAN?
KUVAN can cause serious side effects,
including:

  • Severe allergic reactions including anaphylaxis. Stop taking KUVAN and get medical help right away if you develop any of these signs or symptoms of a severe allergic reaction:
    • Wheezing, coughing, or trouble breathing
    • Feeling flushed, nauseous, lightheaded or you faint
    • Rash
  • Inflammation of the lining of the esophagus or stomach (esophagitis and gastritis). Your doctor will monitor you for symptoms of inflammation in your upper gastrointestinal tract, including your stomach and esophagus. If untreated that inflammation can lead to serious side effects including narrowing of the esophagus, ulcers, and bleeding. Call your doctor right away if you have any of these signs or symptoms:
    • Pain in the upper abdomen (stomach area), esophagus, or throat
    • Nausea, trouble swallowing, loss of appetite, or vomiting
    • Blood in your vomit or stool
    • Black, tarry stools
  • Phe levels that are too low. Patients have experienced low blood Phe during treatment with KUVAN. Low blood phe is more common in children under the age of 7 who take high doses of KUVAN each day.
  • Too much or constant activity (hyperactivity) can happen with KUVAN. Tell your doctor if you have any signs of hyperactivity, including:
    • Fidgeting or moving around too much
    • Talking too much

What should I tell my doctor before I take KUVAN?
Before you take KUVAN, tell your doctor about all your medical conditions, including if you:

  • Are allergic to sapropterin dihydrochloride or any of the ingredients in KUVAN
  • Have poor nutrition or have a loss of appetite
  • Are pregnant or plan to become pregnant
  • Are breastfeeding or plan to breastfeed. It is not known if KUVAN passes into your breast milk. Talk to your doctor about the best way to feed your baby if you take KUVAN.

Tell your doctor about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal and dietary supplements. KUVAN and other medicines may interact with each other. Especially tell your doctor if you take:

  • A medicine that contains levodopa
  • An antifolate medicine such as methotrexate, valproic acid, phenobarbital, trimethoprim
  • Sildenafil (Revatio, Viagra), tadalafil (Adcirca, Cialis), vardenafil (Staxyn, Levitra)

Tell your doctor if you are not sure if your medicine is one that is listed above. Know the medicines you take. Keep a list of them to show your doctor and pharmacist when you get a new medicine.

How should I take KUVAN?
See the detailed “Instructions for Use” that comes with KUVAN for information about the correct way to dissolve and take a dose of KUVAN tablets or KUVAN powder for oral solution.

  • KUVAN does not work for everyone. It is not possible to know if KUVAN will work for you until you start taking KUVAN. Your doctor will check your blood Phe levels when you start taking KUVAN to see if the medicine is working.
  • Take KUVAN exactly as your doctor tells you
  • You can swallow KUVAN tablets whole or dissolve the tablets in water or apple juice
  • KUVAN powder for oral solution should be dissolved in water or apple juice
  • KUVAN should be taken with a PKU-specific diet. Any change you make to your diet may affect your blood Phe level. Follow your doctor’s instructions carefully and do not make any changes to your dietary Phe intake without first talking with your doctor. Even if you take KUVAN, if your blood Phe levels are not well controlled, you can develop severe neurologic problems.
  • Your doctor should continue to monitor your blood Phe levels often during your treatment with KUVAN to make sure that your blood Phe levels are not too high or too low and frequent monitoring for pediatric patients is recommended. Both high and low Phe can result in serious problems. Active management of dietary Phe intake while taking KUVAN is required.
  • If you have a fever, or if you are sick, your blood Phe level may go up. Tell your doctor as soon as possible so he or she can change your dose of KUVAN to help keep your blood Phe levels in the desired range.
  • If you forget to take your dose of KUVAN, take it as soon as you remember that day. Do not take 2 doses in a day.
  • If you take too much KUVAN, call your doctor for advice

The most common side effects of KUVAN are: headache, runny nose and nasal congestion, sore throat, diarrhea, vomiting, and cough.

These are not all the possible side effects of KUVAN. For more information, ask your doctor or pharmacist. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. You may also report side effects to BioMarin Pharmaceutical Inc. at 1-866-906-6100.

Please read the full Prescribing Information by clicking here.