Kuvan

Generic name: sapropterin [ SAP-roe-TER-in ]
Drug class: Miscellaneous metabolic agents

Medically reviewed by Philip Thornton, DipPharm. Last updated on Aug 22, 2023.

What is Kuvan?

Kuvan (sapropterin) is used along with a restricted diet to control blood phenylalanine levels in adults and children one month of age and older who have phenylketonuria (PKU; an inborn condition in which phenylalanine may build up in the blood and causes decreased intelligence and a decreased ability to focus, remember, and organize information).

Kuvan will only work for some people who have PKU, and the only way to tell if Kuvan will help a particular patient is to give the medication for a period of time and see whether his or her phenylalanine level decreases.

Kuvan belongs to a class of medications called cofactors. It works by helping the body to break down phenylalanine so it will not build up in the blood.

Warnings

Before using Kuvan, tell your doctor if you are allergic to any drugs, or if you have liver disease, a history of stomach ulcer or bleeding, or a seizure disorder.

Also tell your doctor about any medications you use, especially levodopa (Larodopa, Altamet, Parcopa, Sinemet), methotrexate (Rheumatrex, Trexall), or any medication to treat erectile dysfunction, such as sildenafil (Viagra), tadalafil (Cialis), or vardenafil (Levitra).

If Kuvan is not controlling your condition properly, you may have symptoms such as behavior changes, numbness or tingling, or problems with speech, vision, or balance. Call your doctor if you have any of these symptoms.

Before taking this medicine

You should not use Kuvan if you are allergic to sapropterin.

To make sure Kuvan is safe for you, tell your doctor if you have ever had:

• stomach ulcer or bleeding; or

• loss of appetite, or if you are malnourished.

It is not known if sapropterin will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

If you are pregnant, your name may be listed on a pregnancy registry to track the effects of sapropterin on the baby.

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

How should I take Kuvan?

Take Kuvan exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose.

Kuvan can cause phenylalanine levels to get too low in children younger than 7 years old who use this medicine.

Take the medicine with food at the same time each day.

You may swallow the Kuvan tablet whole or dissolve it in 4 to 8 ounces of water or apple juice.

• It will take a few minutes for the tablet to dissolve, and you may see small pieces in the liquid. These pieces are safe for you to swallow.

• Stir the mixture and then drink all of it within 15 minutes after the tablet dissolves.

• To get the entire dose, add a little more water to the same glass, swirl gently and drink right away.

• You may also crush the tablet and mix it with a small amount of soft food such as pudding or applesauce.

The powder for oral solution must be dissolved in 4 to 8 ounces of water or apple juice.

• If you are giving Kuvan to a baby who weighs less than 22 pounds, you may dissolve the powder in as little as 1 teaspoon of water or apple juice. Then give the liquid to the baby using an oral dosing syringe. If you do not have a dosing syringe, ask your pharmacist for one.

• Stir the mixture and then drink all of it within 30 minutes after the powder dissolves.

• You may also mix the powder with a small amount of soft food such as pudding or applesauce.

• Make sure the powder is completely dissolved before drinking or eating the mixture.

Doses are based on weight in children and teenagers. Your child's dose may change if the child gains or loses weight.

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

While using Kuvan, you may need frequent blood tests.

Store Kuvan at room temperature away from moisture and heat. Keep the bottle tightly closed when not in use.

Dosing information

Usual Adult Dose of Kuvan for Phenylketonuria:

Initial dose: 10 to 20 mg/kg orally once a day
-Blood phenylalanine (Phe) levels should be measured after 1 week, and then periodically; dose should be increased to 20 mg/kg/day if blood Phe levels have not decreased
Maintenance dose: Once responsiveness has been established, dose should be adjusted within the range of 5 to 20 mg/kg/day according to biochemical response.

Non-Responders:
-Patients whose phenylalanine levels do not decrease with treatment at 20 mg/kg/day for 1 month should be considered non-responders and treatment should be discontinued.

Comments:
-This drug should be used in conjunction with a phenylalanine-restricted diet.
-Existing dietary protein and Phe intake should not be modified during the evaluation period
-Response to therapy is determined by change in blood phenylalanine levels.

Use: To reduce blood phenylalanine levels in patients with hyperphenylalaninemia due to tetrahydrobiopterin- (BH4-) responsive phenylketonuria (PKU).

Usual Pediatric Dose of Kuvan for Phenylketonuria:

1 month to 6 years:
-Initial dose: 10 mg/kg orally once a day

7 years or older:
-Initial dose: 10 to 20 mg/kg orally once a day

-Measure blood phenylalanine levels after 1 week, and then periodically; dose should be increased to 20 mg/kg/day if blood phenylalanine levels have not decreased
Maintenance dose: Once responsiveness has been established, dose should be adjusted within the range of 5 to 20 mg/kg/day according to biochemical response.

Non-Responders:
-Patients whose phenylalanine levels do not decrease with treatment at 20 mg/kg/day for 1 month should be considered non-responders and treatment should be discontinued.

Comments:
-This drug should be used in conjunction with a phenylalanine-restricted diet.
-Existing dietary protein and Phe intake should not be modified during the evaluation period
-Response to therapy is determined by change in blood phenylalanine levels.

Use: To reduce blood phenylalanine levels in patients with hyperphenylalaninemia due to tetrahydrobiopterin- (BH4-) responsive phenylketonuria (PKU).

Related/similar drugs

sapropterin, Javygtor, Palynziq

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses in a day.

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 taking Kuvan?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Kuvan side effects

Get emergency medical help if you have signs of an allergic reaction to Kuvan: hives, rash, wheezing, cough, difficult breathing, nausea, feeling light-headed, flushing (warmth, redness, or tingly feeling), swelling of your face, lips, tongue, or throat.

Kuvan may cause serious side effects. Call your doctor at once if you have:

• behavior changes, seizures, or problems with speech;

• fever, loss of appetite, difficulty swallowing, throat pain, severe stomach discomfort or pain, nausea, vomiting;

• bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds; or

• hyperactive behavior, such as fidgeting or moving around often, or talking too much.

Common Kuvan side effects may include:

• headache;

• diarrhea;

• vomiting; or

• runny or stuffy nose, sore throat, cough.

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.

What other drugs will affect Kuvan?

Tell your doctor about all your other medicines, especially:

• levodopa;

• methotrexate, valproic acid, phenobarbital, trimethoprim; or

• medicine to treat impotence or pulmonary arterial hypertension - sildenafil (Viagra, Revatio), avanafil (Stendra), tadalafil (Adcirca, Cialis) vardenafil (Levitra, Staxyn).

This list is not complete. Other drugs may interact with sapropterin, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Ingredients

Active ingredient: sapropterin dihydrochloride.
Kuvan tablet inactive ingredients: ascorbic acid, crospovidone, dibasic calcium phosphate, D-mannitol, riboflavin, and sodium stearyl fumarate.
Kuvan powder for oral solution inactive ingredients: ascorbic acid, D-mannitol, potassium citrate, and sucralose.

Manufacturer

BioMarin Pharmaceutical Inc., Novato, CA 94949, USA.

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Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Kuvan only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

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