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Taking KUVAN and Managing PKU

How to Take KUVAN® (sapropterin dihydrochloride) Tablets or Powder

  • Once a day
  • At the same time each day
  • With food, preferably your largest meal of the day

Take KUVAN Tablets or Powder for Oral Solution exactly as your doctor tells you.
Please see KUVAN Instructions for Use.

Taking KUVAN Powder 500 mg Is as Easy as 1-2-3

KUVAN Powder dissolves completely in 15 seconds in water, apple juice, or a small amount of soft food such as applesauce or pudding.


Keep in Mind

  • Follow your doctor’s directions for taking KUVAN Tablets and Powder
  • If you forget to take your dose of KUVAN, take it as soon as you remember that day. If you miss a day, do not double your dose the next day—just skip the missed dose. If you take too much KUVAN, call your doctor for advice
  • KUVAN should be taken every day in conjunction with a low-Phe diet. Don’t change your diet without talking to your doctor or dietitian

Tips for Success

Living a healthy, productive life with PKU is possible. However, it is important to remember that PKU is a serious disease requiring lifelong management. Here are some keys to success to achieve a goal of Phe control.

Keep a Food Diary

Track your Phe intake by keeping a food diary. The diary helps your dietitian see how much Phe you consume over several days. The dietitian uses that information to adjust the low-Phe diet and Phe-free medical foods as needed. So it’s very important to accurately record what—and how much—you eat and drink each day.


Download a sample food diary showing a 1-day menu for a low-Phe diet.

Download a 3-day diet record to write down your food and beverage intake, which is a dependable way to determine your Phe intake.

Talk to Your Clinic Team

Learn the facts about KUVAN. Then talk to your clinic team. Together, you and your clinic team can decide if KUVAN is the right choice to help you manage your PKU.

Here’s how to get started:

  1. Locate a PKU clinic near you
  2. Call and make an appointment
  3. Mark your appointment in your calendar
  4. Download this 3-day diet record and track your diet for 3 days. Take it with you to your appointment
  5. Gather together any relevant medical records, especially your blood Phe levels
  6. Be sure you have the name and address of your clinic
  7. Take your medical insurance card or information
  8. Make a list of medications you take including:
    • Prescription medicines
    • Nonprescription medicines
    • Vitamins
    • Herbal supplements
  9. Go to the appointment, even if you don’t have the above information

Sick Days and PKU

Blood Phe levels are likely to rise during the illness. However, this elevation is most likely temporary. When you are sick:

  • Treat the illness first
  • Don’t force yourself to eat. You or your child may not have an appetite
  • Keep yourself or your child hydrated. Water, fruit juice, low-protein gelatin, and low-protein broth are good choices

Travel Tips

Plan ahead. Whether you are going across town or on vacation, these travel tips may come in handy.

  • Pack your medical foods and KUVAN in a carry-on bag, along with a doctor’s note for both
  • Bring a cooler with ice to keep your Phe-formula cold during short-distance trips
  • Find out as much as possible about the place you are visiting, especially if it is a foreign destination. How clean and safe is the water? Will you be able to keep your formula cold?
  • Stay in hotels with a microwave and fridge. That way you can alternate between eating meals out and having some “homemade” meals in your room
  • For longer stays, find out where you can buy low-Phe foods in the area

For the Teacher

Help your child’s teacher understand PKU. Download a brochure that provides important information that a teacher—or anyone caring for your child—should know about PKU and the low-Phe diet.

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,

  • 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 You may also report side effects to BioMarin Pharmaceutical Inc. at 1-866-906-6100.

Please read the full Prescribing Information by clicking here.