Phenylketonuria, or PKU for short, is an inherited, genetic condition in which the body can’t process phenylalanine (Phe), an amino acid found in many foods.

PKU is caused by a defect in the enzyme in the body that works to break down Phe into other chemicals, like tyrosine. This enzyme is called phenylalanine hydroxylase (PAH). In order for the PAH enzyme to work, it needs tetrahydrobiopterin (BH4), a substance that is naturally present in your body. When the PAH enzyme can’t do its job, too much Phe builds up in the blood.

Phe is found in:

1. All protein-containing foods (eg, meat, eggs, dairy, nuts)
2. Many other foods that are not generally thought of as containing protein (eg, most wheat products, such as pasta and bread, some vegetables, and some fruit, such as oranges and cherries)

If people with PKU followed a normal diet, they would eat more Phe than their bodies can handle.

Too much Phe is toxic to the brain. High Phe levels over an extended period of time can lead to lower intelligence and behavioral problems.

One way to manage PKU is to limit Phe intake. This means following a Phe-restricted diet in order to limit the amount of Phe in the blood. KUVAN, the only prescription medication for the treatment of PKU, used along with diet, may help some people with PKU to reduce Phe levels in their blood more than the use of diet alone.

Next: The Importance of PKU Management

 

Indication

KUVAN^® (sapropterin dihydrochloride) Tablets is approved to reduce blood Phe levels in patients with hyperphenylalaninemia (HPA) due to tetrahydrobiopterin- (BH4-) responsive Phenylketonuria (PKU). KUVAN is to be used with a Phe-restricted diet.

Important Safety Information

High blood Phe levels are toxic to the brain and can lead to lower intelligence and decrease in the ability to focus, remember and organize information. Any change you make to your diet may impact your blood Phe level. Follow your doctor’s instructions carefully. Your doctor and dietitian will continue to monitor and may adjust your diet throughout your treatment with KUVAN.

If you have a fever, or if you are sick, your Phe level may go up. Tell your doctor and dietitian as soon as possible so they can see if they have to adjust your treatment to help keep your blood Phe levels in the desired range.

KUVAN is a prescription medicine and should not be taken by people who are allergic to any of its ingredients. Tell your doctor if you have ever had liver or kidney problems, are nursing or pregnant or may become pregnant, have poor nutrition or are anorexic. Your doctor will decide if KUVAN is right for you. Tell your doctor about all the medicines you take.

The most common side effects reported when using KUVAN are headache, diarrhea, abdominal pain, upper respiratory tract infection (like a cold), throat pain, vomiting, and nausea.

To report SUSPECTED ADVERSE REACTIONS, contact BioMarin Pharmaceutical Inc. at 1-866-906-6100, or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

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