Key takeaways

  • Sephience (sepiapterin) is a prescription drug that’s used along with a special diet to help lower phenylalanine levels in adults and certain children with phenylketonuria (PKU).
  • Sephience comes as an oral powder in single-dose packets. The prescribed dosage may vary based on a person’s age, weight, and blood phenylalanine levels.
  • Side effects of Sephience can range from mild issues like headache and diarrhea to serious problems such as low phenylalanine levels and increased risk of bleeding.

Sephience basics

Sephience contains the active ingredient sepiapterin.

Sephience is a brand-name medication. A generic version of the drug isn’t currently available.

Sephience is used to treat phenylketonuria (PKU) in adults and children ages 1 month and older.

PKU is a rare inherited disorder that makes it difficult for the body to break down phenylalanine. This substance is found in many protein-rich foods and some artificial sweeteners. A buildup of phenylalanine in the body can be harmful.

If untreated, PKU may cause symptoms such as seizures, developmental delays, and behavior changes.

Doctors usually prescribe Sephience along with a PKU diet that’s low in phenylalanine.

Sephience works by helping your body break down phenylalanine. In doing so, it lowers phenylalanine levels in the blood and helps manage PKU.

Like most drugs, Sephience may cause mild to serious side effects. The following lists contain some of the more common side effects Sephience may cause, but they don’t include all possible side effects.

Keep in mind that side effects of a drug can depend on:

  • your age
  • other health conditions you have
  • other medications you take

Your doctor or pharmacist can provide you with more information about the potential side effects of Sephience. They can also suggest ways to help reduce side effects.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Sharing your experience helps make medications safer for everyone by giving doctors and researchers more information about how the drug works in real life. If you develop a side effect while taking Sephience and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088.

Mild side effects

Here’s a list of some of the mild side effects that Sephience can cause. To learn about other mild side effects, talk with your doctor or pharmacist, or read Sephience’s prescribing information.

Mild side effects of Sephience that have been reported include:

  • headache
  • discolored feces
  • diarrhea
  • pain in the throat and mouth
  • abdominal pain

Mild side effects of many drugs may go away within a few days to a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.

Serious side effects

Serious side effects from Sephience can occur, but they aren’t common. If you experience serious side effects from Sephience, call your doctor right away. If you think you’re having a medical emergency, you should call 911 or your local emergency number.

Serious side effects of Sephience that have been reported include:

Allergic reaction

For some people, Sephience can cause an allergic reaction. But this side effect wasn’t reported in the drug’s studies.

In general, symptoms of an allergic reaction can be mild or serious.

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms and can determine whether you should continue Sephience treatment.

If you have symptoms of a severe allergic reaction, such as swelling or difficulty breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you’ve had a serious allergic reaction to Sephience, they may have you switch to a different treatment.

The Sephience dosage your doctor prescribes will depend on several factors. These include:

  • the level of phenylalanine in your blood
  • body weight in kilograms (kg) and for children who are 2 years and younger, their age

For reference, 1 kg is about 2.2 pounds (lb).

The following information describes dosages that are commonly used or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.

Form and strengths

Sephience comes as an oral powder in single-use packets. It’s available in two strengths: 250 milligrams (mg) and 1,000 mg.

Recommended dosage

Your doctor will prescribe the dosage of Sephience that’s right for you. Below are the recommended dosages of Sephenice for phenylketonuria (PKU) in adults and in children ages 1 month and older.

Dosage for PKU in adults

Doctors usually prescribe a starting dose of 60 mg per kg of body weight, taken once daily.

Your doctor will check your blood phenylalanine levels and may adjust your Sephience dosage over time. The usual ongoing dose ranges from 7.5 mg to 60 mg per kg of body weight, taken once daily.

To learn more about the Sephenice dosage that’s right for you, talk with your doctor.

Children’s dosage for PKU

The typical starting dose for children depends on their age and body weight:

  • younger than 6 months: 7.5 mg per kg of body weight once daily
  • 6 months to under 1 year: 15 mg per kg once daily
  • 1 year to under 2 years: 30 mg per kg once daily
  • 2 years and older: 60 mg per kg once daily

Your child’s doctor will check their blood phenylalanine levels and may adjust your child’s Sephience dosage over time. The usual ongoing dose ranges from 7.5 mg to 60 mg per kg of body weight, taken once daily.

How to take

Your doctor will explain how much Sephience to take, how often to take it, and how to prepare each dose. Be sure to follow your doctor’s instructions.

Sephience comes as an oral powder in single-use packets. You’ll mix the contents with a small amount of apple juice, water, or a soft food such as applesauce or strawberry jam. The exact amount of liquid or soft food depends on your prescribed dose.

Stir the powder into a liquid for at least 30 seconds or into a soft food for at least 60 seconds. Consume the entire mixture right away. Then, rinse the container with water and drink the rinse until the container is fully clean.

If you’re unsure about how many packets or how much liquid or soft food to use, talk with your doctor or pharmacist. You can also check the dosage chart in the drug’s prescribing information.

About taking Sephience

The following are some common questions about taking Sephience.

  • Should I take Sephience with food? You’ll take each dose of Sephience with food and should eat again shortly after. Having food before and after your dose helps your body absorb the drug so it can reach the level needed to work properly.
  • Is there a best time of day to take Sephience? Sephience can be taken at any time of day, but it’s best to take it at the same time every day. This helps keep a steady level of the drug in your body, which helps Sephience work effectively.
  • What if I miss a dose of Sephience? If you miss a dose, take it as soon as you remember. But if it’s almost time to take your next dose, skip the missed dose and take your next dose at its usual time. You should not take two doses on the same day to make up for a missed dose. Doing so could raise your risk of side effects.
  • Will I need to use Sephience long term? Sephience may be used as a long-term treatment. If you and your doctor determine that it’s safe and effective for your condition, you’ll likely take it long term.
  • How long does Sephience take to work? Sephience begins to work after you take your first dose. Your doctor will check your blood phenylalanine levels to determine whether Sephience is working for your condition. If your levels do not reach the desired range after 2 weeks of treatment, your doctor may advise you to stop taking Sephience. They can recommend a different treatment option instead.

Overdose

Do not take more Sephience than your doctor prescribes, as this may lead to harmful effects.

Call your doctor if you think you’ve taken too much Sephience. You can also call 800-222-1222 to reach America’s Poison Centers or use its online resource. But if you have severe symptoms, immediately call 911 or your local emergency number. Or go to the nearest emergency room.

Sephience can interact with several other medications. But the drug is not known to interact with supplements or foods.

Before taking Sephience, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, or supplements you use. Sharing this information can help you avoid potential interactions.

Interactions with medications

The following table highlights medications that can interact with Sephience. This list does not contain all drugs that may interact with Sephience. If you have questions about interactions that may affect you, ask your doctor or pharmacist.

Medications that can interact with Sephience• PDE-5 inhibitors such as vardenafil and sildenafil (Revatio, Viagra)
• pemetrexed (Alimta, Axtle)
• pralatrexate (Folotyn)
• methotrexate (Rasuvo, Trexall, others)
• sulfamethoxazole/trimethoprim (Bactrim, Septra)
• sulfasalazine (Azulfidine)
• levodopa (Inbrija) or carbidopa/levodopa (Rytary, Sinemet, others)

Sephience and alcohol

Alcohol is not known to interact with Sephience. Talk with your doctor to determine whether it’s safe for you to consume alcohol during Sephience treatment.

Whether you have health insurance or not, cost may be a factor when you’re considering Sephience. What you’ll pay for Sephience may depend on several things, such as your treatment plan and the pharmacy you use

If you have questions about how to pay for your prescription, talk with your doctor or pharmacist. A program called PTC Cares may also be available.

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The following is important information to consider and discuss with your doctor or pharmacist before taking Sephience.

Pregnancy and Sephience

It is unknown whether Sephience is safe to take during pregnancy. If you’re planning a pregnancy or can become pregnant, talk with your doctor before taking this drug.

Sephience and breastfeeding

It is unknown whether Sephience should be taken while breastfeeding. If you’re currently breastfeeding or planning to do so, talk with your doctor before taking this drug.

This section describes the warnings and precautions for Sephience.

Before taking Sephience, discuss your health history with your doctor. Sephience may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:

Note: For more information about the potential negative effects of Sephience, see the “Side effects of Sephience” section.

Other drugs are available that can treat phenylketonuria (PKU), such as sapropterin (Kuvan, Zelvysia).

If you’d like to explore an alternative to Sephience, talk with your doctor. They can tell you about other medications that might work well for you.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.