Daybue (trofinetide) is the first and currently only approved medication to treat Rett Syndrome in adults and children 2 years and older. It comes as a liquid solution which is helpful for people with Rett syndrome who have difficulty swallowing pills or use feeding tubes. The most common side effects of Daybue (trofinetide) include diarrhea and weight loss.
Rett Syndrome in adults and children 2 years and older
Daybue (trofinetide) is a glycine-proline-glutamate analog, meaning it’s similar to a natural substance in our brain called glycine-proline-glutamate (GPE). How Daybue (trofinetide) helps with Rett Syndrome isn’t exactly clear, but it's thought that it works like GPE. This medication helps reduce inflammation, protects brain cells, and improves signals in the brain. As a result, it relieves symptoms of Rett Syndrome, like breathing difficulties, speech problems, and trouble making eye contact.
Source: DailyMed
Side effects that you should report to your care team as soon as possible:
Side effects that usually do not require medical attention (report these to your care team if they continue or are bothersome):
Comes in a strawberry flavor, which is child-friendly
Available in a liquid form for people who have difficulty swallowing pills or use feeding tubes
Can take with or without food
Can be used in children as young as 2 years old
Not safe for people with moderate to severe kidney problems
Commonly causes diarrhea and vomiting
Must take the medication two times a day
Might cause weight loss, which can worsen poor nutrition status in people with Rett syndrome
To get the right amount of Daybue (trofinetide) from the bottle, you must use a special syringe, cup, or dropper from the pharmacy. Ask your pharmacist for help so they can make sure you have the right tool to measure your medication correctly.
Daybue (trofinetide) commonly causes diarrhea, and sometimes it can lead to dehydration. Signs of dehydration include feeling very thirsty, a dry mouth, and feeling tired. If this happens, let your child’s provider know. They can recommend drinking more fluids or taking anti-diarrhea medications. If the diarrhea doesn’t go away, the provider might lower the dose or even have your child stop Daybue (trofinetide).
Taking Daybue (trofinetide) might make your child lose weight. It’s best to keep track of their weight after starting this medication. If you notice that they’re losing weight while taking Daybue (trofinetide), it's important to let your child’s provider know so they can help.
Daybue (trofinetide) might interact and increase the level of other medications like carbamazepine (Tegretol), midazolam, and valsartan (Diovan). This can cause more unwanted side effects from these medications. Before your child starts any new medication or supplements, you should speak with their provider because they might change the dose or have your child avoid taking them together.
Keep unopened and opened Daybue (trofinetide) bottles in the refrigerator at all times. After 14 days of opening the Daybue (trofinetide) bottle, throw away any leftover medication, even if there is leftover liquid. This is because the medication might not work as well if used after that time.
If your child throws up after taking Daybue (trofinetide), don't give another dose to make up for it. Instead, just wait until it's time for their next dose and take it as usual.
If you forget to give a dose of Daybue (trofinetide) to your child, just skip that dose and have them take the next dose at the usual time. Never take two doses to make up for the missed one since this can lead to more side effects from this medication.
Daybue (trofinetide) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk factors: Taking laxative medications
Diarrhea is a very common side effect of Daybue (trofinetide). In the studies, around 85% of people who took Daybue (trofinetide) had mild to moderate diarrhea. Before starting this medication, make sure your child stops taking laxative medications that help with constipation.
If your child gets diarrhea while taking Daybue (trofinetide), tell their provider right away. One risk of having diarrhea is that your child can lose too much body fluids and become dehydrated. Symptoms of dehydration include feeling thirsty, tired, or dizzy. The provider might recommend that your child drinks more fluids to stay hydrated or takes certain anti-diarrhea medications. If the diarrhea doesn’t improve, your child’s provider might consider lowering the dose or stopping Daybue (trofinetide) altogether.
Taking Daybue (trofinetide) might cause your child to lose weight. In some cases, people can lose up to 7% or more of their body weight from before they started treatment. It’s important to keep an eye on your child’s weight by checking it every few days while taking this medication. If you notice any weight loss, let your child’s provider know. If your child loses a lot of weight, their provider might lower the dose or stop Daybue (trofinetide) completely.
Daybue (trofinetide) comes as an oral solution containing 200 mg per mL. Your child will take this medication by mouth or through a feeding tube two times a day, in the morning and evening, with or without food.
The starting dose will depend on your child’s weight:
9 kg to less than 12 kg: The typical dose is 5 grams (25 mL) twice daily.
12 kg to less than 20 kg: The typical dose is 6 grams (30 mL) twice daily.
20 kg to less than 35 kg: The typical dose is 8 grams (40 mL) twice daily.
35 kg to less than 50 kg: The typical dose is 10 grams (50 mL) twice daily.
50 kg or more: The typical dose is 12 grams (60 mL) twice daily.
The dose might differ if your child has side effects that don't go away, like diarrhea or weight loss.
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Acadia Pharmaceuticals, Inc. (n.d.). Support by your side.
Acadia Pharmaceuticals Inc. (2023). Daybue- trofinetide solution [package insert]. DailyMed.
Darwish, M., et al. (2021). Limited potential for interactions between trofinetide, an investigational agent for treatment of Rett syndrome, and antiseizure medications metabolized by CYP3A4. American Epilepsy Society.
Glaze, D. G., et al. (2010). Epilepsy and the natural history of Rett syndrome. Neurology.
International Rett Syndrome Foundation. (n.d.). What is Rett syndrome?
Motil, K. J., et al. (2012). Gastrointestinal and nutritional problems occur frequently throughout life in girls and women with Rett syndrome. Journal of Pediatric Gastroenterology and Nutrition.
National Institute of Neurological Disorders and Stroke. (2023). Rett syndrome.
Neul, J. L., et al. (2022). Design and outcome measures of LAVENDER, a phase 3 study of trofinetide for Rett syndrome. Contemporary Clinical Trials.
University of Wisconsin Health. (n.d.). Gastrojejunostomy tube (GJ tube).
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