Oxbryta (volexator) is a brand-name drug prescribed to treat sickle cell disease (SCD) in adults and some children. Oxbryta comes in two different oral forms and is taken once per day.

Oxbryta is approved by the Food and Drug Administration (FDA) to treat SCD in adults and children ages 4 years and older.

Oxbryta belongs to a drug class called hemoglobin S polymerization inhibitors. Oxbryta is not available in a generic version.

Keep reading for specific information about the dosage of Oxbryta, including its strengths and how to take the medication. For a comprehensive look at Oxbryta, see this article.

Note: This article describes typical dosages of Oxbryta provided by the drug’s manufacturer. When taking Oxbryta, always follow the dosage prescribed by your doctor.

Below is information about Oxbryta’s forms, strengths, and dosages.

Oxbryta forms

Oxbryta comes as an oral tablet and as a tablet for oral suspension (a type of liquid mixture). For details about how you prepare this form of the drug, see “How to take Oxbryta” below.

Oxbryta strengths

Oxbryta tablets come in two strengths: 300 milligrams (mg) and 500 mg.

Oxbryta tablets for oral suspension come in one strength of 300 mg.

Typical dosages

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

Dosage for sickle cell disease

If your doctor prescribes Oxbryta for sickle cell disease (SCD), your dosage will likely be 1,500 mg once per day.

For more information about your specific dosage, talk with your doctor.

Children’s dosage

The FDA has approved Oxbryta to treat SCD in children ages 4 years and older.

For children ages 4–12 years, the dosage depends on the child’s body weight in kilograms (kg). One kg equals about 2.2 pounds (lb). Your child’s doctor will choose the correct dose based on your child’s body weight.

The table below lists the recommended weight-based dosages for children taking Oxbryta:

Child’s body weightRecommended dose once per day
10–20 kg (about 22–44 lb)600 mg
20–40 kg (about 44–88 lb)900 mg
40 kg (about 88 lb) or more1,500 mg

For children ages 12 years and older, the recommended dosage is 1,500 mg once per day.

If your child has difficulty swallowing pills whole, their doctor will likely prescribe Oxbryta tablets for oral suspension. They’ll tell you how many tablets you’ll need for your child’s daily dose. For example, if your child’s dose is 900 mg, you’ll prepare three 300-mg tablets for oral suspension.

Be sure to talk with your child’s doctor if you have questions about their dosage.

Long-term treatment

Oxbryta is meant to be a long-term treatment. If you and your doctor determine that Oxbryta is safe and effective for you, you’ll likely take it long term.

Before you start taking Oxbryta, your doctor will discuss your treatment plan with you.

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

  • your body weight (in children)
  • other medications you take
  • other medical conditions you have

Dosage adjustments

Your doctor may need to adjust your dosage if you take certain medications, such as some CYP3A4 inhibitors and inducers.* These drugs can affect the level of Oxbryta in your body.

Be sure to tell your doctor about all of the medications you take, including vitamins, supplements, or herbs. Your doctor can determine if there are any drug interactions. If so, they may prescribe a dose that’s higher or lower than typically recommended. To find out what drugs may interact with Oxbryta, see the “Interactions” section of this article.

Your doctor may also need to adjust your Oxbryta dosage if you have severe liver disease. Your liver helps remove drugs from your body. With liver problems, it may be harder for your body to remove Oxbryta.

This could raise the level of the drug in your body, increasing your risk of side effects. Your doctor may prescribe a lower dose of Oxbryta if you have severe liver problems. Doing so may help decrease your risk of side effects.

Be sure to tell your doctor about all medications you take and any health conditions you may have.

* CYP3A4 is an enzyme (a type of protein) in the liver that breaks down medications. CYP3A4 inhibitors are a group of drugs that reduce the activity of this enzyme. CYP3A4 inducers are a group of drugs that increase the activity of the enzyme.

Oxbryta is available in two oral dosage forms. “Oral” means you take them by mouth. You can do this with or without food.

It may be helpful to take your Oxbryta dose around the same time of day. This helps maintain a steady level of the drug in your body so Oxbryta can work effectively. Below are details about taking each form of the drug.

Oxbryta oral tablets

You’ll swallow your Oxbryta oral tablet whole. Do not divide, crush, chew, or place the tablet in water.

If you have trouble swallowing tablets, see this article for tips on how to take this form of medication. You can also talk with your doctor or pharmacist.

Oxbryta tablets for oral suspension

Always follow your doctor’s instructions for preparing Oxbryta tablets for oral suspension. Typically, you’ll follow these steps:

  1. Gather the number of tablets for oral suspension you’ll need to prepare the prescribed dose. (The prescription label on the bottle of tablets will include this number.)
  2. Place the tablet(s) in a cup of clear liquid that’s at room temperature. Examples include water, clear soda, apple juice, and clear electrolyte drinks.
  3. Swirl the contents of the cup to dissolve the tablet(s).
  4. Wait 1–5 minutes, swirl the cup again, and drink the contents. It’s likely there will be small clumps of the medication still in the cup. You’ll add more liquid, swirl the cup, and drink the contents.
  5. Repeat step 4 until you don’t see any clumps or residue left in the cup.

If you have questions about preparing this form of Oxbryta, talk with your doctor or pharmacist. You can also review these step-by-step instructions on the drug manufacturer’s website.

Note: Do not cut, crush, or chew Oxbryta tablets for oral suspension. Do not swallow them whole, either.


Some pharmacies offer labels with large print, braille, or a code you scan with a smartphone to convert text to speech. If your local pharmacy doesn’t have these options, your doctor or pharmacist might be able to recommend a pharmacy that does.

If you’re having trouble opening medication bottles, ask your pharmacist about putting Oxbryta in an easy-open container. They also may recommend tools that can make it easier to open bottles.

If you miss a dose of Oxbryta, you should skip the missed dose. Take your next scheduled dose at your regular time on the following day. Do not take two doses to make up for the missed one. If you’re not sure whether to take a missed dose or skip it, talk with your doctor or pharmacist.

To help make sure that you don’t miss a dose, try using a medication reminder. This can include setting an alarm or putting a note where you’ll see it, such as on your bathroom mirror or bedside table. You could also download a reminder app on your phone.

It’s important that you do not take more Oxbryta than your doctor prescribes. For some medications, taking more than the recommended amount may lead to harmful effects or overdose.

If you take more than the recommended amount of Oxbryta

Call your doctor right away if you believe you’ve taken too much Oxbryta. Another option is to call America’s Poison Centers at 800-222-1222 or use its online tool. If you have severe symptoms, immediately call 911 or your local emergency number, or go to the nearest emergency room.

Below are some frequently asked questions about Oxbryta.

Is the dosage of Oxbryta similar to the dosage of Adakveo?

No, the forms and how often you take each drug are different. Oxbryta comes as an oral tablet and tablets for oral suspension. Both forms are taken by mouth once per day.

Crizanlizumab-tmca (Adakveo) comes as a solution that’s given as an intravenous (IV) infusion once every 4 weeks. (The reason “-tmca” appears at the end of the drug’s name is to show it’s distinct from similar medications that may be created in the future.)

To learn more about how Oxbryta and Adakveo compare for treating sickle cell disease (SCD), talk with your doctor.

How long does it take for Oxbryta to start working?

Oxbryta starts to work after your first dose. Because of how the drug works, you likely won’t feel the drug working in your body. It may be several weeks before your SCD symptoms begin to ease. However, your doctor will monitor you during treatment to check whether the drug is working to treat your condition.

Talk with your doctor if you have questions about what to expect with Oxbryta treatment.

The dosages in this article are typical dosages provided by the drug’s manufacturer. If your doctor recommends Oxbryta for you, they’ll prescribe the dosage that’s right for you. Always follow the dosage that your doctor prescribes.

As with any drug, never change your dosage of Oxbryta without your doctor’s recommendation. If you have questions about the dosage of Oxbryta that’s best for you, talk with your doctor.

Besides learning about dosage, you may want other information about Oxbryta. These additional articles might be helpful:

  • More about Oxbryta: For information about other aspects of Oxbryta, refer to this article.
  • Details about sickle cell disease (SCD): For details about SCD, see our list of SCD articles.

Disclaimer: Medical News Today 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.