Kuvan, known generically as sapropterin dihydrochloride, is a medication prescribed for the management of phenylketonuria (PKU), a genetic disorder that impairs the body's ability to process the amino acid phenylalanine. Elevated phenylalanine levels can lead to severe cognitive impairments and other health issues. Kuvan enhances the activity of the enzyme phenylalanine hydroxylase, helping to reduce these levels. It is used alongside a phenylalanine-restricted diet to effectively manage PKU symptoms and prevent its complications.
Active Ingredient: Sapro
Dosage Form: Tablet
Minimum Market Price: 0.1

Side Effects

Runny/stuffy nose or sore throat may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including: trouble swallowing, pain in the throat, stomach/abdominal pain that doesn't go away, nausea/vomiting that doesn't stop, black stools, blood in your vomit, signs of hyperactivity (such as not being able to sit still).

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US – Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada – Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.


This medication is used along with diet changes for long-term treatment of a certain inherited disorder (phenylketonuria-PKU). It helps remove a certain chemical (phenylalanine) from the body. Too much phenylalanine in the body can cause brain damage.

How to use Kuvan

Read the Patient Information Leaflet and Instructions for Use if available from your pharmacist before you start taking sapropterin and each time you get a refill. If you have any questions, ask your doctor or pharmacist.

Take this medication by mouth with a meal as directed by your doctor, usually once daily. The dosage is based on your medical condition, age, weight, lab tests, and response to treatment.

Swallow the tablets whole or you may dissolve them in 120 to 240 milliliters (4 to 8 ounces) of water or apple juice. To help the tablets dissolve faster, you may stir or crush them. Drink this mixture within 15 minutes of mixing. If you see small pieces of the tablet remaining in the cup, add some more water or apple juice to the cup and drink it so you get all of the dose.

You may also crush the tablets and mix them in a small amount of soft food (such as apple sauce or pudding). Eat all of the mixture right away. Do not prepare a supply in advance.

Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time each day.

Tell your doctor if you do not get better or if you get worse.


Before taking sapropterin, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver disease.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

It is unknown if this medication passes into breast milk. Consult your doctor before breast-feeding.


Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.


    If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

    Do not share this medication with others.

    Lab and/or medical tests (such as phenylalanine blood levels) should be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

    If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

    Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

    Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

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