Zulresso (brexanolone) is a brand-name drug prescribed for the treatment of postpartum depression in adults and some children. Zulresso comes as a liquid solution that’s given as an intravenous (IV) infusion by a healthcare professional.

Zulresso is approved by the Food and Drug Administration (FDA) to treat postpartum depression in people ages 15 years and older.

Zulresso belongs to a drug class called neuroactive steroid gamma-aminobutyric acids (GABAs). Zulresso is not available in a generic version.

Keep reading for specific information about the dosage of Zulresso, including its strength and how the medication is used. For a comprehensive look at Zulresso, see this article.

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

The typically recommended dosage for Zulresso is described below.

Zulresso form

Zulresso comes as a liquid solution that’s given as an IV infusion. You’ll receive the infusion in a healthcare facility.

Zulresso strength

Zulresso comes in one strength: 100 milligrams per 20 milliliters of solution (mg/mL).

Typical dosages

Your doctor will start you on a low dosage. Then, they’ll increase it over time to reach the recommended dose (if your body tolerates it without serious side effects). Then, they’ll lower the dose in the last few hours of treatment.

The following information describes dosages that are commonly used or recommended. Your doctor will determine the best dosage to fit your needs.

Dosage for postpartum depression

Doctors prescribe Zulresso to treat postpartum depression. The dosage will be based on your weight in kilograms (kg). One kg equals about 2.2 pounds (lb). The dosage is measured in micrograms (mcg) per kilogram (mcg/kg) and is calculated by your doctor.

The recommended dosage given as an infusion over 60 hours (approximately 2.5 days) is:

  • Start of the infusion through hour 3: 30 mcg/kg per hour
  • Hours 4–23: 60 mcg/kg per hour
  • Hours 24–51: 90 mcg/kg per hour*
  • Hours 52–55: 60 mcg/kg per hour
  • Hours 56–60: 30 mcg/kg per hour

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

* Your doctor may lower this dose to 60 mcg/kg per hour in people who do not tolerate the higher dose.

Children’s dosage

Zulresso is approved to treat postpartum depression in children ages 15 years and older.

The dosage for children is the same as the dosage for adults. For more information, see the “Dosage for postpartum depression” section above.

Long-term treatment

Zulresso is used short-term to treat postpartum depression. Your doctor may discuss other long-term medications that you can take after treatment with Zulresso if needed.

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

  • your body weight
  • how your body responds to Zulresso

Dosage adjustments

If you have serious side effects or loss of consciousness* during the infusion, your doctor may decrease your dose or temporarily stop treatment with Zulresso. If your doctor decides it’s safe for you to continue receiving Zulresso, they may restart the infusion at a lower dose.

* Zulresso has a boxed warning about risk of severe sedation and loss of consciousness. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the boxed warning information at the top of this article.

You’ll receive the IV infusion of Zulresso in a healthcare facility. The infusion is given over a total of 60 hours (2.5 days).

You will stay in the healthcare facility for the entire time the infusion is given. Your doctor will need to adjust the dose at different times during your infusion. They will also monitor you for side effects, such as sedation or loss of consciousness.

For some medications, using more than the recommended amount may lead to harmful effects or overdose.

If you take more than the recommended amount of Zulresso

Call your doctor right away if you believe you’ve received too much Zulresso. 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.

Zulresso contains the active ingredient brexanolone, which is a Schedule IV controlled substance*. This means that there is potential for misuse and dependence on the medication.

Misuse is when a drug is taken or used in a way other than how it’s prescribed. With dependence, your body becomes used to a drug and needs it to function as usual. This means you may have withdrawal symptoms if you suddenly stop taking the drug after taking it regularly for some time. (Withdrawal symptoms are side effects that happen after you stop taking a drug your body has become dependent on.)

It’s not known if Zulresso can cause physical dependence. In clinical studies, the Zulresso dosage was tapered at the end of treatment by a healthcare professional. (A dose taper helps reduce your risk of withdrawal symptoms when you stop treatment with the drug.) No withdrawal symptoms were reported in these studies.

If you have questions about Zulresso treatment and dependence, talk with your doctor.

* Drugs with a lower schedule number have a greater risk for misuse than drugs with a higher schedule number. For example, Schedule II drugs have a greater risk for misuse than Schedule III drugs.

Below are some frequently asked questions about Zulresso.

Is the dosage of Zulresso similar to the dosage of Zoloft?

No, the forms and how often you take each drug are different.

Zulresso comes as a liquid solution that’s given as an IV infusion. The dosage of Zulresso is one infusion given over 60 hours. It must be given in a healthcare facility.

Zoloft comes as an oral tablet or oral solution that you take by mouth once per day.

The dose in mg for each drug differs because they have different active ingredients. Your doctor will prescribe the drug and dosage that’s right for you.

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

How long does it take for Zulresso to start working?

Zulresso starts working as soon as you receive your infusion. Because of how the drug works, you likely won’t feel the drug working in your body. 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 Zulresso treatment.

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

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

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

  • More about Zulresso: For information about other aspects of Zulresso, refer to this article.
  • Drug comparison: To find out how Zulresso compares with Zoloft or Lexapro, read this article.
  • Details about postpartum depression: For details about postpartum depression, see our pregnancy and parenthood hub.

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.