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Clare

Ellie

Henry

Holly

Kate

Maddy

Madelyn

Nicole

Quinn

Madelyn is a music-loving girl who enjoys soft, snuggly things and playing outside—where everyone is included

Madelyn’s family has seen what may be possible since starting DAYBUE^®.

For Madelyn, some improvements include:

Madelyn, age 5, living with Rett syndrome

Hand movements or stereotypies

Madelyn has shown improvements in feeding herself and playing with toys, which she is very proud of

Repetitive behaviors

Madelyn has been grinding her teeth less. She’s now able to control her tongue more and can “put her tongue away” on request

Breathing

Madelyn is holding her breath less frequently and hyperventilating less

Vocalizations

Madelyn now vocalizes intentionally and has distinct sounds for excitement and needing help

Eye gaze

Madelyn used to avoid eye contact but now looks when her name is called

Mood

Madelyn now engages more and tolerates environments better. She enjoys watching other kids; she smiles at them

Madelyn’s story

Diagnosis and symptoms

Madelyn was diagnosed with Rett syndrome when she was around 3 years old. Some of her signs and symptoms have included:

Repetitive hand behaviors
Loss of purposeful hand use
Loss of communication abilities

Other treatments

Madelyn does weekly physical, occupational, and speech therapy. She also takes DAYBUE “like a rock star.”

Managing side effects

Madelyn has had some diarrhea since starting DAYBUE but takes a fiber supplement and eats bananas to help.

Important Note: The effectiveness and safety of DAYBUE were evaluated in the 12-week LAVENDER™ clinical study of 187 female patients aged 5 to 20 with Rett syndrome. Because each individual with Rett syndrome is unique—with a unique set of symptoms—the response to DAYBUE may be different for everyone. Madelyn initiated treatment on DAYBUE in June 2023 and was not a clinical study participant. Madelyn’s experience on treatment is unique to her. See the results from the clinical study. Madelyn’s family was compensated for sharing their story and participating in a photo shoot. This story was created in June 2025.

Since starting DAYBUE, Madelyn seems happier, and she smiles more. It’s helped her mood and our lives.

— Angie, Madelyn’s mom

Important Safety Information and Indication

What are the possible side effects of DAYBUE?

Diarrhea: Diarrhea is a common side effect of DAYBUE that can sometimes be severe. Diarrhea may cause you to lose too much water from your body (dehydration). Before starting treatment with DAYBUE, stop taking laxatives. Tell your healthcare provider if you have diarrhea while taking DAYBUE. Your healthcare provider may ask you to increase the amount you drink or take antidiarrheal medicine as needed.
Vomiting: Vomiting is a common side effect of DAYBUE. Sometimes vomit can get into your lungs (aspiration), which could cause an infection (aspiration pneumonia). Tell your healthcare provider if you have severe vomiting or if vomiting happens often.
Weight loss: DAYBUE can cause weight loss. Tell your healthcare provider if you notice you are losing weight at any time during treatment with DAYBUE.
The most common side effects of DAYBUE were diarrhea and vomiting. Other side effects include fever, seizure, anxiety, decreased appetite, tiredness, and the common cold. These are not all the possible side effects of DAYBUE. Tell your healthcare provider if you have any side effects that bother you or do not go away.

What should I tell my healthcare provider before taking DAYBUE?

Before taking DAYBUE, tell your healthcare provider about all of your medical conditions, including if you:

have kidney problems.
are pregnant or plan to become pregnant. It is not known if DAYBUE will harm your unborn baby.
are breastfeeding or plan to breastfeed. It is not known if DAYBUE passes into your breast milk. Talk to your healthcare provider about the best way to feed your baby while taking DAYBUE.

Tell your healthcare provider about all of the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Taking DAYBUE with certain medicines may affect how the other medicines work and can cause serious side effects.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch or call 1-800-FDA-1088. You can also call Acadia Pharmaceuticals Inc. at 1-844-4ACADIA (1-844-422-2342).

What is DAYBUE?

DAYBUE is a prescription medicine used to treat Rett syndrome in adults and children 2 years of age and older. It is not known if DAYBUE is safe and effective in children under 2 years of age.

DAYBUE is available as an oral solution (200 mg/mL).

The risk information provided here is not comprehensive. To learn more, talk with your healthcare provider and read the fullPrescribing Information,Patient Information, also available at DAYBUE.com.

Important Safety Information and Indication

What are the possible side effects of DAYBUE?

Diarrhea: Diarrhea is a common side effect of DAYBUE that can sometimes be severe. Diarrhea may cause you to lose too much water from your body (dehydration). Before starting treatment with DAYBUE, stop taking laxatives. Tell your healthcare provider if you have diarrhea while taking DAYBUE. Your healthcare provider may ask you to increase the amount you drink or take antidiarrheal medicine as needed.
Vomiting: Vomiting is a common side effect of DAYBUE. Sometimes vomit can get into your lungs (aspiration), which could cause an infection (aspiration pneumonia). Tell your healthcare provider if you have severe vomiting or if vomiting happens often.
Weight loss: DAYBUE can cause weight loss. Tell your healthcare provider if you notice you are losing weight at any time during treatment with DAYBUE.
The most common side effects of DAYBUE were diarrhea and vomiting. Other side effects include fever, seizure, anxiety, decreased appetite, tiredness, and the common cold. These are not all the possible side effects of DAYBUE. Tell your healthcare provider if you have any side effects that bother you or do not go away.

What should I tell my healthcare provider before taking DAYBUE?

Before taking DAYBUE, tell your healthcare provider about all of your medical conditions, including if you:

have kidney problems.
are pregnant or plan to become pregnant. It is not known if DAYBUE will harm your unborn baby.
are breastfeeding or plan to breastfeed. It is not known if DAYBUE passes into your breast milk. Talk to your healthcare provider about the best way to feed your baby while taking DAYBUE.

What is DAYBUE?

DAYBUE is a prescription medicine used to treat Rett syndrome in adults and children 2 years of age and older. It is not known if DAYBUE is safe and effective in children under 2 years of age.

DAYBUE is available as an oral solution (200 mg/mL).

The risk information provided here is not comprehensive. To learn more, talk with your healthcare provider and read the full Prescribing Information, including Patient Information, also available at DAYBUE.com.

Meet Madelyn

Madelyn is a music-loving girl who enjoys soft, snuggly things and playing outside—where everyone is included

Madelyn’s story

Since starting DAYBUE, Madelyn seems happier, and she smiles more. It’s helped her mood and our lives.

Important Safety Information and Indication

What are the possible side effects of DAYBUE?

What should I tell my healthcare provider before taking DAYBUE?

What is DAYBUE?

Important Safety Information and Indication

What are the possible side effects of DAYBUE?

What should I tell my healthcare provider before taking DAYBUE?

What is DAYBUE?

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A Letter to the Rett Syndrome Community: Updates From Acadia