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Sapropterin

Generic Kuvan

Used for PKU

Sapropterin (Kuvan) is used to lower blood phenylalanine (Phe) levels in adults and children one month of age and older with a certain type of phenylketonuria (PKU). It's taken by mouth once daily along with a Phe-restricted diet, which includes monitoring the amount of proteins and Phe levels in foods. Sapropterin (Kuvan) comes in both tablet and powder form, so it gives options to people who might have trouble shallowing. Some common side effects include headache, runny nose, and throat pain.

Reviewed by:

Yen Nguyen, PharmD

Kristianne Hannemann, PharmD

Last reviewed on March 22, 2022

Basics Side effects Pros & cons Pharmacist tips FAQs Warnings Dosage Interactions Images Prices Medicare

What is Sapropterin (Kuvan)?

What is Sapropterin (Kuvan) used for?

Used with a Phe-restricted diet to treat high blood phenylalanine (Phe) levels in adults and children one month of age and older

How Sapropterin (Kuvan) works

Sapropterin (Kuvan) treats PKU by acting like tetrahydrobiopterin (BH4), a substance that's naturally found in your body. BH4 helps a protein in your body called phenylalanine hydroxylase (PAH) work better at breaking down certain nutrients from your food into basic building blocks that your body can use to do important things, such as repairing tissues.

In people with PKU, PAH doesn't work very well at breaking down a building block called Phe, into a simpler form. This means that Phe builds up in your body and can lead to problems such as anxiety, feeling irritated, and not being able to focus. Sapropterin (Kuvan) helps lower the Phe levels in your body by helping PAH work better.

Drug Facts

Common BrandsKuvan, Javygtor

Drug ClassPhenylalanine hydroxylase activator

Controlled Substance ClassificationNot a controlled medication

Generic StatusLower-cost generic available

AvailabilityPrescription only

What are the side effects of Sapropterin (Kuvan)?

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

Headache (15%)
Runny nose (11%)
Throat pain (10%)
Diarrhea (8%)
Vomiting (8%)
Cough (7%)
Stuffy nose (4%)

Other Side Effects

Low blood Phe levels
Rhinitis
Stomach pain

Serious Side Effects

Contact your healthcare provider immediately if you experience any of the following.

Severe allergic reaction: rash, trouble breathing, swelling of the lips, tongue, or throat
Severe stomach problems: stomach pain, nausea, vomiting, blood in vomit or stool, black tarry stools, trouble swallowing, loss of appetite, throat pain

Source: DailyMed

The following side effects have also been reported

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

Fever

Incidence not known

Burning feeling in the chest or stomach

cough

difficulty with swallowing

dizziness

fast heartbeat

fidgeting or moving around too much

heartburn

indigestion

pain or burning in the throat

puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue

skin rash, hives, or itching

sores, ulcers, or white spots on lips or tongue or inside the mouth

stomach upset

talking too much

tenderness in the stomach area

tightness in the chest

trouble swallowing

unusual tiredness or weakness

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Diarrhea

headache

runny nose

sore throat

vomiting

Less common

Stuffy nose

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Pros and cons of Sapropterin (Kuvan)

Pros

Available as tablet and powder

Dose can be adjusted based on your body weight and blood Phe levels

Only needs to be taken once a day

Available as a lower-cost generic

Cons

Need to get frequent blood tests

Might not work for everyone with PKU

Can cause throat or stomach inflammation

Need to take with food

Pharmacist tips for Sapropterin (Kuvan)

Sapropterin (Kuvan) tablets can be dissolved in 120-240 mL of water or apple juice. You can stir or crush the tablet to make it dissolve faster. It's ok if the tablets don't dissolve completely. Make sure to drink the solution within 15 minutes. If you see leftover medication in your cup, add more water or apple juice and drink to make sure you take your full dose.

Sapropterin (Kuvan) powder can be mixed with 120-240 mL of water or apple juice for children weighing more than 10 kg. If your child weighs less than 10 kg, ask your provider how much water or apple juice you should mix with the powder to get the correct dose. These amounts might change as your child grows. Make sure to give the solution within 30 minutes.

Take sapropterin (Kuvan) by mouth with a meal at the same time each day. Taking it on an empty stomach will lower the amount of medication that gets into your body, so it won't work as well. If you miss a dose of sapropterin (Kuvan), take it as soon as possible, but never take two doses on the same day.

Stop taking sapropterin (Kuvan) and get emergency medical help right away if you experience an allergic reaction, such as rash, wheezing, trouble breathing, nausea, or swelling of the face, lips, or throat. Let your provider know so they can decide the best treatment option going forward.

Sapropterin (Kuvan) can cause stomach problems, which can be serious if left untreated. Let your provider know if you or your child experiences stomach problems, such as nausea, vomiting, trouble swallowing, indigestion, loss of appetite, throat pain, or stomach pain.

It's important to follow up with the provider and go to all of the blood test appointments to properly monitor the blood Phe levels. Levels that are too low or too high can have serious effects on the body, so having an accurate measurement will allow the provider to make adjustments to the dose.

If you or your child is sick, or have a fever, it might affect the blood Phe level, so let your provider know and they can adjust the dose.

Let your provider know if you're pregnant, planning to become pregnant, or breastfeeding before starting sapropterin (Kuvan). It's not known if this medication can cause harm to your baby or pass into breast milk. If you become pregnant during your treatment with sapropterin (Kuvan), speak to your provider about enrolling into a special registry program for this medication or call 1-800-983-4587.

Frequently asked questions about Sapropterin (Kuvan)

Can sapropterin (Kuvan) be taken for all types of PKU?

Sapropterin (Kuvan) is used for people with high blood phenylalanine (Phe) levels due to a type of PKU called BH4-responsive PKU. It might not work for everyone since this medication can only benefit people with PKU who respond to BH4 (a chemical that helps lower Phe in your body). Your provider will monitor your blood levels of Phe to make sure this medication is working for you.

What is the "evaluation period" for sapropterin (Kuvan)?

The "evaluation period" is the first month after you or your child starts taking sapropterin (Kuvan). Your provider will check the blood Phe levels 1 week after starting treatment, and periodically for up to a month. The blood Phe levels will determine if the dose should be adjusted or if the medication should be stopped. During this evaluation period, don't make any changes to how much protein or Phe you take in through diet so your provider can determine if sapropterin (Kuvan) is working.

What are the different ways to take sapropterin (Kuvan)?

Sapropterin (Kuvan) tablets can be swallowed whole. Both sapropterin (Kuvan) tablet and powder can be dissolved in water or apple juice, or crushed and mixed into a small amount of soft food, like applesauce or pudding. For children weighing 10 kg or less, the powder form should be used and your child's provider will instruct you on how much liquid should be mixed with it. Discuss the best way for you or your child to take this medication with your provider.

Is there a difference between sapropterin (Kuvan) tablet and powder form?

Sapropterin (Kuvan) tablets are available in 100 mg strength, and the powder is available in 100 mg and 500 mg strength. Both forms are taken once daily and will work the same way in your body. Sapropterin (Kuvan) powder might be easier to take for younger children and is the only form that can give you an accurate dose measurement for children weighing 10 kg or less.

What is a Phe-restricted diet?

A phe-restricted diet is a low-protein diet. Foods with animal protein, legumes, and nuts are typically avoided. Bread, pasta, rice, and some vegetables are high in protein, so they should be eaten in limited quantities. You can replace those foods with low-protein bread and pasta that are made from starch. Speak to your provider about your dietary choices and restrictions to see how you can lower your Phe levels but still have enough nutrients. Sometimes, medical foods or supplements might be needed depending on your nutritional intake.

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What are the risks and warnings for Sapropterin (Kuvan)?

Sapropterin (Kuvan) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

Allergic reaction

Sapropterin (Kuvan) can cause allergic reactions, including some that are life-threatening like anaphylaxis (closing of the throat). Speak to your provider before taking sapropterin (Kuvan) if you or your child has experienced an allergic reaction to this medication in the past. Get emergency medical help if you experience any symptoms of an allergic reaction, including trouble breathing, rash, nausea, or swelling of your lips, tongue, or throat.

Stomach problems

Sapropterin (Kuvan) can cause irritation and inflammation (swelling) in the esophagus (the tube that connects your mouth with your stomach) and stomach. If not treated, this can lead to more serious problems, like narrowing of the esophagus, stomach ulcers, or stomach bleeding. Let your provider know if you experience symptoms of nausea, vomiting, trouble swallowing, indigestion, loss of appetite, or throat or stomach pain.

Frequent monitoring of blood Phe levels

While sapropterin (Kuvan) works well to lower blood Phe levels, it doesn't work for everyone. Sometimes, it might lower blood Phe levels too much. That's why during treatment with sapropterin (Kuvan), your provider will have you or your child get frequent blood tests to monitor the blood Phe levels. This can help the provider adjust the dose, as well as provide proper treatment if the levels are too high or too low.

Having high blood Phe levels for a long period of time can lead to serious problems, such as anxiety, feeling irritated, and not being able to focus. Having a very low level of blood Phe can lead to growth problems. The risk of low blood Phe levels is higher in children younger than 7 years old.

Make sure you keep track of the amount of Phe you get from food, and go to all of the blood test appointments to make sure your blood Phe levels are monitored properly. Sapropterin (Kuvan) might not work for everyone. If this medication doesn't lower the blood Phe levels after a month of taking the 20 mg/kg dose, your provider will discuss other treatment options with you.

Interaction with levodopa

Risk factors: Taking together with levodopa

Sapropterin (Kuvan) might interact with levodopa (Inbrija), a medication commonly used for Parkinson's disease and found in combination with carbidopa (Lodosyn). Combination medications that contain levodopa include Sinemet and Rytary. Some people who took sapropterin (Kuvan) with levodopa at the same time experienced symptoms such as seizures, worsening of seizures, and irritability. Let your provider know before starting sapropterin (Kuvan) if you're taking levodopa so they can monitor you during treatment.

Hyperactivity

Sapropterin (Kuvan) might cause hyperactivity (too much or constant activity), restlessness, fidgeting, or excessive talking. Let your provider know if this is a problem for you or your child while taking sapropterin (Kuvan).

Sapropterin (Kuvan) dosage forms

Typical dosing for Sapropterin (Kuvan)

The dose of sapropterin (Kuvan) will be determined by your provider based on your body weight and response.

Children 1 month to 6 years old: The typical starting dose is 10 mg/kg by mouth once daily.
Adults and children 7 years and older: The typical starting dose is 10 mg/kg to 20 mg/kg by mouth once daily.

Interactions between Sapropterin (Kuvan) and other drugs

Sapropterin (Kuvan) may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with Sapropterin (Kuvan). Please note that only the generic name of each medication is listed below.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Sapropterin (Kuvan) images

This medicine is Yellow Carton.yellow - Sapropterin Dihydrochloride 500mg Powder for Solution

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