Exondys 51 (eteplirsen) is a brand-name drug that’s prescribed for Duchenne muscular dystrophy in adults and some children. Exondys 51 comes as a solution that is given intravenously once weekly. The dosage can vary depending on your body weight.

Exondys 51 is approved by the Food and Drug Administration (FDA) to treat certain people with Duchenne muscular dystrophy (DMD). Specifically, this medication can be used in people with a mutation of the DMD gene that can be treated by skipping exon 51.

This medication received accelerated approval for this use. That means the drug is still being studied. The FDA will make a decision on full approval once the trials are complete. However, some medications are approved through an accelerated approval process if the drug is better than currently available treatments.

Exondys 51 belongs to a drug class called antisense oligonucleotides. Exondys 51 is not available in a generic version.

Keep reading for specific information about the dosage of Exondys 51, including its strengths and how you’ll receive the medication. For a comprehensive look at Exondys 51, see this article.

Note: This article describes typical dosages for Exondys 51 provided by the drug’s manufacturer. However, your doctor will prescribe the Exondys 51 dosage that’s right for you.

Below is information about Exondys 51’s form, strengths, and dosages.

Exondys 51 form

Exondys 51 comes as a solution that’s given as an intravenous (IV) infusion. It’s always given by a healthcare professional.

Exondys 51 strengths

Exondys 51 comes in one strength of 50 milligrams per milliliter (mg/mL).

Typical dosages

The following information describes dosages that are commonly prescribed in adults. However, your doctor will determine the best dosage to fit your needs.

Dosage for Duchenne muscular dystrophy

Doctors may prescribe Exondys 51 to treat Duchenne muscular dystrophy (DMD).

If your doctor prescribes Exondys 51 for your DMD, your dosage will be based on your body weight in kilograms (kg). One kilogram equals about 2.2 pounds (lb). The dosage per kilogram is measured in milligrams per kilogram (mg/kg) and is calculated by your doctor.

You’ll receive a dose of 30 mg/kg. You’ll get this dose once per week. For example, if you weigh 75 kg (165 lb), your dose will be 2,250 mg once weekly.

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

Children’s dosage

Exondys 51 is approved to treat DMD in children with the condition.

The dosage for children is the same as it is for adults and is based on the child’s body weight in kilograms. One kilogram equals about 2.2 lb. The dosage per kilogram is measured in milligrams per kilogram and is calculated by your child’s doctor.

The recommended dosage of Exondys 51 in children is 30 mg/kg once per week. If your child weighs 66 lb (30 kg), their dose would be 900 mg once weekly.

Talk with your child’s doctor if you have questions about their dosage.

Long-term treatment

Exondys 51 is meant to be received as a long-term treatment. If you and your doctor determine that Exondys 51 is safe and effective for you, you’ll likely receive it long term.

Before you start taking Exondys 51, your doctor will discuss your treatment plan with you.

The Exondys 51 dosage your doctor prescribes will depend on your body weight.

Your doctor or another healthcare professional will give you the intravenous (IV) infusion of Exondys 51. They’ll prepare the liquid solution for infusion by diluting it. You’ll likely go to your doctor’s office, infusion center, or a hospital to receive your infusion. The infusion takes between 35 and 60 minutes.

If you have questions about how to use Exondys 51, talk with your doctor or pharmacist.

If you miss your appointment for an Exondys 51 infusion, call your doctor’s office as soon as possible to reschedule. They’ll adjust your dosing schedule as needed.

If you need help remembering your appointments, try setting an alarm or downloading a reminder app on your phone.

Below are some frequently asked questions about Exondys 51.

Is the dosage of Exondys 51 similar to the dosage of Vyondys 53?

Yes, the forms and how often you’ll receive each drug are similar. Exondys 51 and Vyondys 53 (golodirsen) are both solutions that are given through an intravenous (IV) infusion. Both drugs are taken once weekly and dosed based on your body weight.

It’s important to note that Exondys 51 and Vyondys 53 are not used for the exact same conditions. Exondys 51 is used when a mutation of the DMD gene can be treated by skipping exon 51. But Vyondys 53 is used when a DMD mutation can be treated by skipping exon 53. Your doctor will prescribe the medication that will work best for you based on your condition.

To learn more about how these drugs compare, talk with your doctor.

How long does it take for Exondys 51 to start working?

Exondys 51 starts to work after your first dose. Because of how the drug works, you likely won’t feel the drug working in your body. So, you may not notice it making a difference in your symptoms right away. But 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 Exondys 51 treatment.

The dosages in this article are typical dosages provided by the drug’s manufacturer. If your doctor recommends Exondys 51 for you, they will prescribe the dosage that’s right for you.

If you have questions about the dosage of Exondys 51 that’s best for you, talk with your doctor.

Besides learning about dosage, you may want other information about Exondys 51. These additional articles might be helpful:

  • More about Exondys 51: For information about other aspects of Exondys 51, refer to this article.
  • Side effects: To learn about side effects of Exondys 51, see the Exondys 51 prescribing information.
  • Cost: If you’d like to learn about Exondys 51 and cost, see this article.

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.