Betaine side effects: what 1,034 FDA adverse event reports show

Betaine · 22 reaction terms · 396 drug–reaction co-reports · data 2026-09-14

Drug class

Methylating Agent

FDA label (Established Pharmacologic Class)

Who reports

1,034 reports · 62% serious · 71 with death outcome · 50% female

openFDA FAERS counts, all years, deduplication not applied

Used for

Betaine Anhydrous for Oral Solution is indicated for the treatment of homocystinuria to decrease elevated homocysteine blood concentrations in pediatric and adult patients. Included within the category of homocystinuria are Cystathionine beta-synthase .

FDA label, Indications and Usage

What it is

Betaine Anhydrous for Oral Solution is an agent for the treatment of homocystinuria. It contains no ingredients other than anhydrous betaine. Betaine Anhydrous for Oral Solution is a white to off-white, crystalline, hygroscopic powder, which is diluted in water and administered orally.

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 19 strongest signals

Reporting / coding artifact 9Not in label — unassessed 10

What the badges mean

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. 3 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
Gastroenteritis viral	29	32.5 22.7–46.6ROR 33.4 · χ² 854 / p 4e-188	31.9 EB05 23.3 · IC025 +3.8 3/3 methods agree	Not in label — unassessed	serious PRR 9.8 · 86% consumer	no trial data cached
Brain oedema	18	28.9 18.3–45.8ROR 29.4 · χ² 458 / p 8e-102	28.1 EB05 18.8 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious PRR 26.9	no trial data cached
Product odour abnormal	10	19.5 10.5–36.2ROR 19.7 · χ² 158 / p 2e-36	18.3 EB05 9.7 · IC025 +2.3 3/3 methods agree	Reporting / coding artifact	serious n=3	no trial data cached
Pharyngitis streptococcal	10	18.7 10.1–34.7ROR 18.9 · χ² 151 / p 6e-35	17.4 EB05 9.1 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious n=3	no trial data cached
Prescribed overdose	17	17.8 11.1–28.6ROR 18.1 · χ² 253 / p 2e-57	17.3 EB05 11.0 · IC025 +2.8 3/3 methods agree	Not in label — unassessed	serious PRR 16.5	no trial data cached
Product dose omission	55	16.9 13.0–21.8ROR 17.7 · χ² 806 / p 1e-177	16.7 EB05 13.3 · IC025 +3.4 3/3 methods agree	Reporting / coding artifact	serious PRR 13.8 · 80% consumer	no trial data cached
Therapy change	7	14.7 7.0–30.8ROR 14.8 · χ² 76 / p 1e-18	11.8 EB05 4.9 · IC025 +1.6 3/3 methods agree	Reporting / coding artifact	serious n=5	no trial data cached
Gastroenteritis	10	13.9 7.5–25.8ROR 14.1 · χ² 107 / p 2e-25	12.1 EB05 6.0 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 8.2	no trial data cached
Treatment noncompliance	30	11.2 7.9–15.9ROR 11.5 · χ² 269 / p 9e-61	10.6 EB05 7.5 · IC025 +2.7 3/3 methods agree	Reporting / coding artifact	serious PRR 11.3	no trial data cached
Disseminated intravascular coagulation	7	10.1 4.8–21.0ROR 10.1 · χ² 48 / p 2e-12	7.2 EB05 3.4 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 9.3	no trial data cached
Poor quality product administered	5	9.9 4.1–23.8ROR 10.0 · χ² 32 / p 9e-9	6.3 EB05 2.7 · IC025 +0.9 3/3 methods agree	Not in label — unassessed	serious n=2	no trial data cached
Cholestasis (bile flow blockage)	9	9.6 5.0–18.3ROR 9.6 · χ² 61 / p 3e-15	7.3 EB05 3.8 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 8.9	no trial data cached
Product taste abnormal	6	9.1 4.1–20.1ROR 9.1 · χ² 35 / p 1e-9	6.1 EB05 2.9 · IC025 +1.1 3/3 methods agree	Reporting / coding artifact	serious n=1	no trial data cached
Hepatocellular injury	6	8.6 3.9–19.0ROR 8.6 · χ² 33 / p 5e-9	5.8 EB05 2.7 · IC025 +1.0 3/3 methods agree	Not in label — unassessed	serious PRR 7.9	no trial data cached
Overdose	86	8.1 6.6–9.9ROR 8.7 · χ² 530 / p 2e-117	7.8 EB05 6.5 · IC025 +2.6 3/3 methods agree	Reporting / coding artifact	serious PRR 5.2	no trial data cached
Inappropriate schedule of drug administration	26	7.3 5.0–10.7ROR 7.5 · χ² 136 / p 1e-31	6.6 EB05 4.7 · IC025 +2.1 3/3 methods agree	Reporting / coding artifact	serious PRR 11.7	no trial data cached
Underdose	22	6.1 4.0–9.2ROR 6.2 · χ² 89 / p 2e-21	5.5 EB05 3.8 · IC025 +1.7 3/3 methods agree	Reporting / coding artifact	serious PRR 13.6	no trial data cached
Abortion spontaneous	8	4.0 2.0–8.0ROR 4.1 · χ² 15 / p 4e-5	3.4 EB05 1.9 · IC025 +0.6	Not in label — unassessed	serious PRR 3.7	no trial data cached
Drug dose omission	23	2.8 1.9–4.2ROR 2.8 · χ² 25 / p 3e-7	2.7 EB05 1.9 · IC025 +0.7	Reporting / coding artifact	serious PRR 6.2 · ♀ 22% (drug 50%) · 83% 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
Overdose	86	8.1 6.6–9.9ROR 8.7 · χ² 530 / p 2e-117	7.8 EB05 6.5 · IC025 +2.6 3/3 methods agree	Reporting / coding artifact	serious PRR 5.2	no trial data cached
Product dose omission	55	16.9 13.0–21.8ROR 17.7 · χ² 806 / p 1e-177	16.7 EB05 13.3 · IC025 +3.4 3/3 methods agree	Reporting / coding artifact	serious PRR 13.8 · 80% consumer	no trial data cached
Treatment noncompliance	30	11.2 7.9–15.9ROR 11.5 · χ² 269 / p 9e-61	10.6 EB05 7.5 · IC025 +2.7 3/3 methods agree	Reporting / coding artifact	serious PRR 11.3	no trial data cached
Gastroenteritis viral	29	32.5 22.7–46.6ROR 33.4 · χ² 854 / p 4e-188	31.9 EB05 23.3 · IC025 +3.8 3/3 methods agree	Not in label — unassessed	serious PRR 9.8 · 86% consumer	no trial data cached
Inappropriate schedule of drug administration	26	7.3 5.0–10.7ROR 7.5 · χ² 136 / p 1e-31	6.6 EB05 4.7 · IC025 +2.1 3/3 methods agree	Reporting / coding artifact	serious PRR 11.7	no trial data cached
Drug dose omission	23	2.8 1.9–4.2ROR 2.8 · χ² 25 / p 3e-7	2.7 EB05 1.9 · IC025 +0.7	Reporting / coding artifact	serious PRR 6.2 · ♀ 22% (drug 50%) · 83% consumer	no trial data cached
Underdose	22	6.1 4.0–9.2ROR 6.2 · χ² 89 / p 2e-21	5.5 EB05 3.8 · IC025 +1.7 3/3 methods agree	Reporting / coding artifact	serious PRR 13.6	no trial data cached
Brain oedema	18	28.9 18.3–45.8ROR 29.4 · χ² 458 / p 8e-102	28.1 EB05 18.8 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious PRR 26.9	no trial data cached
Prescribed overdose	17	17.8 11.1–28.6ROR 18.1 · χ² 253 / p 2e-57	17.3 EB05 11.0 · IC025 +2.8 3/3 methods agree	Not in label — unassessed	serious PRR 16.5	no trial data cached
Gastroenteritis	10	13.9 7.5–25.8ROR 14.1 · χ² 107 / p 2e-25	12.1 EB05 6.0 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 8.2	no trial data cached
Pharyngitis streptococcal	10	18.7 10.1–34.7ROR 18.9 · χ² 151 / p 6e-35	17.4 EB05 9.1 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious n=3	no trial data cached
Product odour abnormal	10	19.5 10.5–36.2ROR 19.7 · χ² 158 / p 2e-36	18.3 EB05 9.7 · IC025 +2.3 3/3 methods agree	Reporting / coding artifact	serious n=3	no trial data cached
Cholestasis (bile flow blockage)	9	9.6 5.0–18.3ROR 9.6 · χ² 61 / p 3e-15	7.3 EB05 3.8 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 8.9	no trial data cached
Abortion spontaneous	8	4.0 2.0–8.0ROR 4.1 · χ² 15 / p 4e-5	3.4 EB05 1.9 · IC025 +0.6	Not in label — unassessed	serious PRR 3.7	no trial data cached
Disseminated intravascular coagulation	7	10.1 4.8–21.0ROR 10.1 · χ² 48 / p 2e-12	7.2 EB05 3.4 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 9.3	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=29, PRR 32.5

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 Betaine?

In FDA FAERS, the most frequently co-reported reaction terms for Betaine are gastroenteritis viral, brain oedema, prescribed overdose, gastroenteritis, pharyngitis streptococcal, cholestasis. 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 Betaine have an FDA boxed warning?

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

Do FAERS signals prove that Betaine 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 99b667fa-b00c-465b-bbed-36f317078115, effective 20260520; matched on openfda.generic_name.exact:"BETAINE")
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, 22 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.