Trofinetide side effects: what 6,691 FDA adverse event reports show

Trofinetide · Daybue, Daybue Stix · 160 reaction terms · 21,700 drug–reaction co-reports · data 2026-09-14

Drug class

Cytochrome P450 3A4 Inhibitors, Organic Anion Transporting Polypeptide 1B1 Inhibitors

FDA label (mechanism-of-action class)

Brand names

Daybue, Daybue Stix

openFDA label

Who reports

6,691 reports · 28% serious · 39 with death outcome · 96% female

openFDA FAERS counts, all years, deduplication not applied

Used for

DAYBUE and DAYBUE STIX are indicated for the treatment of Rett syndrome in adults and pediatric patients 2 years of age and older. DAYBUE and DAYBUE STIX are indicated for the treatment of Rett syndrome in adults and pediatric patients 2 years of age and older. ( 1 )

FDA label, Indications and Usage

What it is

DAYBUE oral solution and DAYBUE STIX for oral solution contain the active moiety trofinetide.

FDA label, Description section

Boxed warning

None in the current label

How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation. Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)? That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.

Causality screen of the 40 strongest signals

Labeled adverse reaction 5Labeled (related wording) 2Reporting / coding artifact 7Not in label — unassessed 26

What the badges mean

Labeled adverse reaction The exact term appears in the label's warnings or adverse-reactions sections: a known, expected effect. The FAERS signal confirms the label rather than discovering anything.
Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.

Strongest disproportionality signals

Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 120 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.

Show: hide coding/lab/outcome terms hide indication terms unlabeled only hide PRR-only

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Product use complaint	641	135.2 125.4–145.8ROR 149.4 · χ² 81,750 / p <1e-300	129.1 EB05 120.9 · IC025 +6.7 3/3 methods agree	Reporting / coding artifact	serious n=152 · 98% consumer	no trial data cached
Underdose	2,002	88.3 85.0–91.7ROR 125.6 · χ² 168,474 / p <1e-300	85.8 EB05 82.7 · IC025 +6.3 3/3 methods agree	Reporting / coding artifact	serious PRR 212.0 · 98% consumer	no trial data cached
Intentional dose omission	472	55.0 50.4–60.1ROR 59.1 · χ² 24,581 / p <1e-300	54.0 EB05 50.0 · IC025 +5.5 3/3 methods agree	Reporting / coding artifact	serious PRR 62.4 · 99% consumer	no trial data cached
Gastroenteritis viral	300	52.8 47.2–59.0ROR 55.2 · χ² 14,948 / p <1e-300	51.8 EB05 47.0 · IC025 +5.4 3/3 methods agree	Not in label — unassessed	serious PRR 60.5 · 99% consumer	no trial data cached
Prescribed underdose	288	45.9 41.0–51.4ROR 47.9 · χ² 12,433 / p <1e-300	45.1 EB05 40.9 · IC025 +5.2 3/3 methods agree	Not in label — unassessed	serious PRR 57.6 · 97% consumer	no trial data cached
Retching	279	41.6 37.1–46.8ROR 43.4 · χ² 10,892 / p <1e-300	41.0 EB05 37.1 · IC025 +5.1 3/3 methods agree	Not in label — unassessed	serious PRR 53.4 · 99% consumer	no trial data cached
Hypophagia	191	23.8 20.7–27.3ROR 24.4 · χ² 4,116 / p <1e-300	23.5 EB05 20.9 · IC025 +4.2 3/3 methods agree	Not in label — unassessed	serious PRR 22.1 · 99% consumer	no trial data cached
Seizure	834	22.9 21.5–24.4ROR 26.1 · χ² 17,441 / p <1e-300	22.8 EB05 21.5 · IC025 +4.4 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 48.7 · 96% consumer	no trial data cached
Gastroenteritis	98	21.2 17.4–25.8ROR 21.5 · χ² 1,856 / p <1e-300	21.0 EB05 17.7 · IC025 +3.9 3/3 methods agree	Not in label — unassessed	serious PRR 7.5 · 99% consumer	no trial data cached
Flatulence (gas)	368	20.5 18.6–22.7ROR 21.6 · χ² 6,781 / p <1e-300	20.4 EB05 18.7 · IC025 +4.1 3/3 methods agree	Not in label — unassessed	serious PRR 29.8 · 98% consumer	no trial data cached
Pharyngitis streptococcal	68	19.8 15.6–25.1ROR 20.0 · χ² 1,188 / p 1e-260	19.6 EB05 16.0 · IC025 +3.7 3/3 methods agree	Not in label — unassessed	serious n=27 · 97% consumer	no trial data cached
Diarrhoea (diarrhea)	3,631	17.8 17.4–18.2ROR 37.7 · χ² 58,993 / p <1e-300	17.7 EB05 17.2 · IC025 +4.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 16.0 · 97% consumer	no trial data cached
Crying	189	16.3 14.2–18.8ROR 16.8 · χ² 2,693 / p <1e-300	16.2 EB05 14.4 · IC025 +3.7 3/3 methods agree	Not in label — unassessed	serious PRR 22.2 · 97% consumer	no trial data cached
Ear infection	130	15.4 13.0–18.3ROR 15.7 · χ² 1,732 / p <1e-300	15.3 EB05 13.2 · IC025 +3.6 3/3 methods agree	Not in label — unassessed	serious PRR 22.7 · 98% consumer	no trial data cached
Hypersomnia	117	12.9 10.7–15.4ROR 13.1 · χ² 1,264 / p 4e-277	12.7 EB05 10.9 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious PRR 23.8 · 99% consumer	no trial data cached
Viral infection	134	12.7 10.7–15.0ROR 12.9 · χ² 1,426 / p <1e-300	12.6 EB05 10.8 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious PRR 17.4 · 100% consumer	no trial data cached
Frequent bowel movements	97	11.3 9.3–13.8ROR 11.5 · χ² 902 / p 2e-198	11.1 EB05 9.4 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious PRR 12.7 · 96% consumer	no trial data cached
Mood altered	97	11.2 9.2–13.7ROR 11.4 · χ² 891 / p 5e-196	11.0 EB05 9.3 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious PRR 12.0 · 98% consumer	no trial data cached
Irritability	210	11.0 9.6–12.5ROR 11.3 · χ² 1,890 / p <1e-300	10.9 EB05 9.7 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious PRR 13.0 · 98% consumer	no trial data cached
Aspiration	36	10.4 7.5–14.5ROR 10.5 · χ² 297 / p 7e-67	9.9 EB05 7.3 · IC025 +2.7 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 21.6 · 97% consumer	no trial data cached
Abnormal behaviour	129	10.2 8.6–12.1ROR 10.3 · χ² 1,056 / p 8e-232	10.0 EB05 8.6 · IC025 +3.0 3/3 methods agree	Not in label — unassessed	serious PRR 10.3 · 98% consumer	no trial data cached
Middle insomnia	60	10.1 7.9–13.0ROR 10.2 · χ² 484 / p 2e-107	9.8 EB05 7.8 · IC025 +2.8 3/3 methods agree	Not in label — unassessed	serious PRR 14.8 · 98% consumer	no trial data cached
Product dose omission issue	917	10.1 9.5–10.8ROR 11.6 · χ² 7,609 / p <1e-300	10.1 EB05 9.5 · IC025 +3.2 3/3 methods agree	Reporting / coding artifact	serious PRR 29.3 · 99% consumer	no trial data cached
Seasonal allergy	45	10.0 7.5–13.4ROR 10.1 · χ² 355 / p 1e-79	9.6 EB05 7.3 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious n=16 · 98% consumer	no trial data cached
Constipation	685	9.9 9.3–10.7ROR 11.0 · χ² 5,544 / p <1e-300	9.9 EB05 9.3 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious PRR 12.5 · 99% consumer	no trial data cached
Aggression	139	8.7 7.4–10.3ROR 8.9 · χ² 940 / p 1e-206	8.5 EB05 7.4 · IC025 +2.8 3/3 methods agree	Not in label — unassessed	serious PRR 8.4 · 99% consumer	no trial data cached
Influenza	307	8.6 7.7–9.6ROR 9.0 · χ² 2,067 / p <1e-300	8.5 EB05 7.8 · IC025 +2.9 3/3 methods agree	Not in label — unassessed	serious PRR 10.3 · 98% consumer	no trial data cached
Eructation (belching)	52	8.6 6.5–11.3ROR 8.6 · χ² 340 / p 3e-76	8.2 EB05 6.4 · IC025 +2.5 3/3 methods agree	Not in label — unassessed	serious n=11 · 100% consumer	no trial data cached
Product taste abnormal	36	8.4 6.1–11.7ROR 8.4 · χ² 227 / p 1e-51	7.8 EB05 5.8 · IC025 +2.4 3/3 methods agree	Reporting / coding artifact	serious n=8 · 97% consumer	no trial data cached
Illness	262	8.2 7.3–9.2ROR 8.5 · χ² 1,650 / p <1e-300	8.1 EB05 7.3 · IC025 +2.8 3/3 methods agree	Reporting / coding artifact	serious PRR 13.2 · 98% consumer	no trial data cached
Dyskinesia (involuntary movements)	103	8.0 6.6–9.7ROR 8.1 · χ² 621 / p 2e-137	7.8 EB05 6.6 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 8.7 · 93% consumer	no trial data cached
Secretion discharge	31	7.9 5.5–11.2ROR 7.9 · χ² 179 / p 4e-41	7.2 EB05 5.3 · IC025 +2.2 3/3 methods agree	Not in label — unassessed	serious PRR 13.5 · 100% consumer	no trial data cached
Salivary hypersecretion	25	7.9 5.3–11.6ROR 7.9 · χ² 143 / p 4e-33	7.1 EB05 5.0 · IC025 +2.1 3/3 methods agree	Not in label — unassessed	serious PRR 6.9 · 96% consumer	no trial data cached
Dystonia	48	7.7 5.8–10.3ROR 7.8 · χ² 275 / p 5e-62	7.3 EB05 5.7 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 17.3 · 98% consumer	no trial data cached
Vomiting	1,155	7.7 7.3–8.2ROR 9.1 · χ² 6,907 / p <1e-300	7.7 EB05 7.3 · IC025 +2.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 7.9 · 97% consumer	no trial data cached
Gastrooesophageal reflux disease (acid reflux)	189	7.4 6.4–8.5ROR 7.6 · χ² 1,042 / p 8e-229	7.3 EB05 6.4 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 9.2 · 97% consumer	no trial data cached
Pneumonia aspiration	56	7.1 5.4–9.2ROR 7.1 · χ² 285 / p 4e-64	6.7 EB05 5.3 · IC025 +2.3 3/3 methods agree	Labeled (related wording) related wording	serious PRR 14.3 · 95% consumer	no trial data cached
Weight decreased (weight loss)	579	6.5 6.0–7.0ROR 7.0 · χ² 2,728 / p <1e-300	6.5 EB05 6.0 · IC025 +2.6 3/3 methods agree	Labeled (related wording) related wording	serious PRR 6.9 · 98% consumer	no trial data cached
Nasopharyngitis (common cold)	383	6.5 5.9–7.2ROR 6.8 · χ² 1,792 / p <1e-300	6.5 EB05 5.9 · IC025 +2.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 10.1 · 99% consumer	no trial data cached
Inappropriate schedule of product administration	350	6.2 5.6–6.9ROR 6.5 · χ² 1,536 / p <1e-300	6.2 EB05 5.6 · IC025 +2.4 3/3 methods agree	Reporting / coding artifact	serious PRR 10.3 · 97% consumer	no trial data cached

Trial evidence (ClinicalTrials.gov)

Trial cross-check not yet run for this drug (ClinicalTrials.gov pull covers the 800 most-reported drugs first).

Most frequently reported reactions

By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Diarrhoea (diarrhea)	3,631	17.8 17.4–18.2ROR 37.7 · χ² 58,993 / p <1e-300	17.7 EB05 17.2 · IC025 +4.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 16.0 · 97% consumer	no trial data cached
Underdose	2,002	88.3 85.0–91.7ROR 125.6 · χ² 168,474 / p <1e-300	85.8 EB05 82.7 · IC025 +6.3 3/3 methods agree	Reporting / coding artifact	serious PRR 212.0 · 98% consumer	no trial data cached
Vomiting	1,155	7.7 7.3–8.2ROR 9.1 · χ² 6,907 / p <1e-300	7.7 EB05 7.3 · IC025 +2.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 7.9 · 97% consumer	no trial data cached
Product dose omission issue	917	10.1 9.5–10.8ROR 11.6 · χ² 7,609 / p <1e-300	10.1 EB05 9.5 · IC025 +3.2 3/3 methods agree	Reporting / coding artifact	serious PRR 29.3 · 99% consumer	no trial data cached
Seizure	834	22.9 21.5–24.4ROR 26.1 · χ² 17,441 / p <1e-300	22.8 EB05 21.5 · IC025 +4.4 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 48.7 · 96% consumer	no trial data cached
Constipation	685	9.9 9.3–10.7ROR 11.0 · χ² 5,544 / p <1e-300	9.9 EB05 9.3 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious PRR 12.5 · 99% consumer	no trial data cached
Product use complaint	641	135.2 125.4–145.8ROR 149.4 · χ² 81,750 / p <1e-300	129.1 EB05 120.9 · IC025 +6.7 3/3 methods agree	Reporting / coding artifact	serious n=152 · 98% consumer	no trial data cached
Weight decreased (weight loss)	579	6.5 6.0–7.0ROR 7.0 · χ² 2,728 / p <1e-300	6.5 EB05 6.0 · IC025 +2.6 3/3 methods agree	Labeled (related wording) related wording	serious PRR 6.9 · 98% consumer	no trial data cached
Intentional dose omission	472	55.0 50.4–60.1ROR 59.1 · χ² 24,581 / p <1e-300	54.0 EB05 50.0 · IC025 +5.5 3/3 methods agree	Reporting / coding artifact	serious PRR 62.4 · 99% consumer	no trial data cached
Decreased appetite (loss of appetite)	424	5.7 5.2–6.3ROR 6.1 · χ² 1,673 / p <1e-300	5.7 EB05 5.3 · IC025 +2.4 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 6.6 · 98% consumer	no trial data cached
Nasopharyngitis (common cold)	383	6.5 5.9–7.2ROR 6.8 · χ² 1,792 / p <1e-300	6.5 EB05 5.9 · IC025 +2.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 10.1 · 99% consumer	no trial data cached
Flatulence (gas)	368	20.5 18.6–22.7ROR 21.6 · χ² 6,781 / p <1e-300	20.4 EB05 18.7 · IC025 +4.1 3/3 methods agree	Not in label — unassessed	serious PRR 29.8 · 98% consumer	no trial data cached
Inappropriate schedule of product administration	350	6.2 5.6–6.9ROR 6.5 · χ² 1,536 / p <1e-300	6.2 EB05 5.6 · IC025 +2.4 3/3 methods agree	Reporting / coding artifact	serious PRR 10.3 · 97% consumer	no trial data cached
Abdominal discomfort	307	5.8 5.2–6.4ROR 6.0 · χ² 1,212 / p 9e-266	5.7 EB05 5.2 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 7.3 · 99% consumer	no trial data cached
Influenza	307	8.6 7.7–9.6ROR 9.0 · χ² 2,067 / p <1e-300	8.5 EB05 7.8 · IC025 +2.9 3/3 methods agree	Not in label — unassessed	serious PRR 10.3 · 98% consumer	no trial data cached

Unlabeled candidate signals

These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.

Gastroenteritis viral — n=300, PRR 52.8
Prescribed underdose — n=288, PRR 45.9
Retching — n=279, PRR 41.6
Hypophagia — n=191, PRR 23.8
Gastroenteritis — n=98, PRR 21.2
Flatulence — n=368, PRR 20.5
Pharyngitis streptococcal — n=68, PRR 19.8
Crying — n=189, PRR 16.3
Ear infection — n=130, PRR 15.4
Hypersomnia — n=117, PRR 12.9

Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.

Common questions

What are the most reported side effects of Trofinetide?

In FDA FAERS, the most frequently co-reported reaction terms for Trofinetide are diarrhoea, vomiting, seizure, constipation, weight decreased, decreased appetite. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.

Does Trofinetide have an FDA boxed warning?

No. The FDA label retrieved for Trofinetide has no boxed warning; see the label's Warnings and Precautions for the recognised risks.

Do FAERS signals prove that Trofinetide causes these side effects?

No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.

Sources & methods

FDA label via openFDA (set ID 67e6f2d9-21f6-466f-9def-826c6a4b8257, effective 20260904; matched on openfda.generic_name.exact:"TROFINETIDE")
Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA count= aggregation, field patient.drug.openfda.generic_name.exact, 160 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction
Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
Seriousness and sex counts from openFDA count=serious, patient.patientsex, seriousnessdeath

Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.