Source: European Medicines Agency (EU) Revision Year: 2026 Publisher: Acadia Pharmaceuticals (Netherlands) B.V., Strawinskylaan 3051, 1077 ZX Amsterdam, Netherlands
Daybu is indicated for the treatment of neurobehavioural symptoms of Rett syndrome in adults and paediatric patients aged 5 years and older.
Trofinetide should be taken twice daily, morning and evening, according to patient weight as shown in Table 1.
Table 1. Recommended dosage of trofinetide in patients 5 years of age and older:
| Patient weight | Trofinetide dosage | Trofinetide volume |
| 9 kg to less than 12 kg | 5 g twice daily | 25 mL twice daily |
| 12 kg to less than 20 kg | 6 g twice daily | 30 mL twice daily |
| 20 kg to less than 35 kg | 8 g twice daily | 40 mL twice daily |
| 35 kg to less than 50 kg | 10 g twice daily | 50 mL twice daily |
| 50 kg or more | 12 g twice daily | 60 mL twice daily |
Continued benefit of treatment should be regularly re-assessed.
The impact of dose reduction on the efficacy of trofinetide is uncertain. Following a dose reduction for the management of adverse reactions, reinstatement of the recommended dose should be considered, based on clinical judgement.
Patients should be advised to stop taking laxatives before starting trofinetide. An interruption, a reduction in dose, or discontinuation of trofinetide should be considered if severe diarrhoea occurs or dehydration is suspected (see section 4.4).
If vomiting occurs after trofinetide administration, an additional dose should not be taken. Instead, the next scheduled dose should be taken. An interruption, a reduction in dose, or discontinuation of trofinetide should be considered if vomiting is severe or occurs despite medical management (see section 4.4).
An interruption, a reduction in dose, or discontinuation of trofinetide should be considered if significant weight loss occurs (see section 4.4).
If a dose of trofinetide is missed, it should be taken as soon as possible. If it is time for the next dose, the missed dose should not be taken. Instead, the next scheduled dose should be taken. Doses should never be doubled to make up for a missed dose.
Clinical studies of trofinetide did not include patients 65 years of age and older to determine whether or not they respond differently from younger patients. This medicinal product is known to be substantially excreted by the kidney. Because elderly patients are more likely to have decreased renal function, it may be useful to monitor renal function.
No dose adjustment is needed in patients with hepatic impairment (see section 5.2).
No dose adjustment is needed in patients with mild renal impairment (estimated glomerular filtration rate (eGFR) 60 to 89 mL/min/1.73 m²). The recommended dosage of trofinetide for patients with moderate renal impairment (eGFR 30 to 59 mL/min/1.73 m²) is described in Table 2:
Table 2. Recommended dosage of trofinetide in patients with moderate renal impairment:
| Patient weight | Trofinetide dosage | Trofinetide volume |
| 9 kg to less than 12 kg | 2.5 g twice daily | 12.5 mL twice daily |
| 12 kg to less than 20 kg | 3 g twice daily | 15 mL twice daily |
| 20 kg to less than 35 kg | 4 g twice daily | 20 mL twice daily |
| 35 kg to less than 50 kg | 5 g twice daily | 25 mL twice daily |
| 50 kg or more | 6 g twice daily | 30 mL twice daily |
Administration of trofinetide to patients with severe renal impairment (eGFR 15 to 29 mL/min/1.73 m²) is not recommended (see section 5.2).
The safety and efficacy in paediatric patients below the age of 5 years have not been established (see section 5.1).
The efficacy and safety of treatment initiation with trofinetide in patients over 20 years have not been yet established. In patients in whom a clear treatment benefit has been demonstrated, treatment may be continued in patients over 20 years.
Daybu is for oral use or administered via gastric (G) tube. It can be taken with or without food.
Using a dosing cup (30 mL or 110 mL) provided with the medicinal product, the appropriate volume (mL) of oral solution corresponding to the prescribed dose of Daybu should be measured.
The entire contents of the dosing cup should be administered orally. After the administration, the dosing cup should be rinsed under running cold water and air dry. Store the cleaned dosing cup with the bottle until next use.
Daybu may be administered via G tube; doses administered via GJ tubes must be administered through the G-port (see section 6.6).
Do not administer via nasogastric (NG) tube.
In clinical studies, the highest reported overdose was double the recommended dose. One patient in Study 1 at the weight range between 35 kg to 50 kg received double their evening dose and reported vomiting associated with this overdose.
If an overdose occurs or is suspected, the patient should be monitored closely for signs or symptoms of adverse reactions, and supportive treatment offered where necessary.
There is no specific antidote recommended for an overdose of trofinetide.
Before opening:
3 years.
After first opening:
Daybu should be discarded after 30 days.
Daybu should be stored in a refrigerator (2°C – 8°C). Do not freeze.
The child-resistant cap should be kept tightly closed.
After first opening:
Daybu should be stored in an upright position.
Excursions to room temperature are supported.
Translucent high-density polyethylene (HDPE) multi-dose bottle containing 450 mL oral solution with a white polypropylene child-resistant closure.
Each pack includes 1 bottle of 450 mL Daybu oral solution and 2 dosing cups (30 mL and 110 mL).
The 30 mL dosing cup is graduated from 5 mL to 30 mL by increments of 2.5 mL.
The 110 mL dosing cup is graduated from 10 mL to 110 mL by increments of 10 mL.
Any unused medicinal product or waste material should be disposed of in accordance with local requirements.
Dosing cups provided with Daybu should be discarded after 30 days.
Administration via gastric feeding tube:
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