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Sapropterin

Generic Name: sapropterin (SAP roe TER in)
Brand Name: Kuvan

Medically reviewed by Drugs.com on Feb 18, 2020 – Written by Cerner Multum

What is sapropterin?

Phenylketonuria (PKU) is a disorder in which the body cannot break down phenylalanine. Elevated phenylalanine levels can cause problems with thinking and behavior.

Sapropterin is used to lower blood levels of phenylalanine in people with a certain type of PKU.

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

Important Information

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Before taking this medicine

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

Tell your doctor if you have ever had:

  • stomach ulcer or bleeding; or

  • little or no appetite, or if you are malnourished.

It is not known whether 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.

It is not known whether sapropterin passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breastfeeding.

Sapropterin is not approved for use by anyone younger than 1 month old.

How should I take sapropterin?

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.

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you do not understand these instructions.

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

Older children may be able to use sapropterin for a longer period of time than younger children. Follow your doctor's dosing instructions very carefully.

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

You may swallow the 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 this medicine 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.

Sapropterin doses are based on weight (especially in children and teenagers). Your dose needs may change if you gain or lose weight.

You may need to follow a special diet while using sapropterin. Follow all instructions of your doctor or dietitian. Learn about the foods to eat or avoid to help control your condition.

While using sapropterin, you may need frequent blood tests.

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

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 sapropterin?

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

Sapropterin side effects

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

Call your doctor at once if you have:

  • behavior changes, seizures, or problems with speech;

  • 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.

Common side effects 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.

Sapropterin dosing information

Usual Adult Dose 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 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).

What other drugs will affect sapropterin?

Tell your doctor about all your other medicines, especially:

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

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.