Miglustat side effects: what 1,153 FDA adverse event reports show

Miglustat · Yargesa · 36 reaction terms · 764 drug–reaction co-reports · data 2026-09-14

Drug class

Glucosylceramide Synthase Inhibitor, Enzyme Stabilizer

FDA label (Established Pharmacologic Class)

Brand names

Yargesa

openFDA label

Who reports

1,153 reports · 87% serious · 319 with death outcome · 52% female

openFDA FAERS counts, all years, deduplication not applied

Used for

YARGESA is a glucosylceramide synthase inhibitor indicated as monotherapy for treatment of adult patients with mild/moderate type 1 Gaucher disease for whom enzyme replacement therapy is not a therapeutic option ( 1.1 ). 1.1 Type 1 Gaucher Disease YARG.

FDA label, Indications and Usage

What it is

YARGESA (miglustat capsules) is an inhibitor of the enzyme glucosylceramide synthase, which is a glucosyl transferase enzyme responsible for the first step in the synthesis of most glycosphingolipids. YARGESA is an N-alkylated imino sugar, a synthetic analog of D-glucose.

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 18 strongest signals

Labeled adverse reaction 1Likely indication confounding 1Reporting / coding artifact 1Not in label — unassessed 15

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.
Likely indication confounding The term appears in the label's indications: reports probably describe the disease being treated (or its progression), not a drug effect. Classic confounding by indication.
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. 18 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
Ataxia	25	38.2 25.9–56.3ROR 39.0 · χ² 867 / p 6e-191	37.1 EB05 26.4 · IC025 +3.8 3/3 methods agree	Not in label — unassessed	serious PRR 26.3 · 96% clinician	no trial data cached
Pneumonia aspiration	42	30.7 22.8–41.3ROR 31.8 · χ² 1,175 / p 7e-258	30.2 EB05 23.3 · IC025 +4.0 3/3 methods agree	Not in label — unassessed	serious PRR 20.4 · 90% clinician	no trial data cached
Motor dysfunction	17	30.6 19.1–49.0ROR 31.0 · χ² 457 / p 1e-101	29.6 EB05 19.6 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious PRR 19.5	no trial data cached
Epilepsy	44	26.2 19.6–35.1ROR 27.2 · χ² 1,043 / p 4e-229	25.9 EB05 20.1 · IC025 +3.9 3/3 methods agree	Not in label — unassessed	serious PRR 17.1 · 98% clinician	no trial data cached
Aspiration	15	25.2 15.2–41.7ROR 25.5 · χ² 324 / p 8e-73	24.4 EB05 15.6 · IC025 +3.0 3/3 methods agree	Not in label — unassessed	serious PRR 16.0	no trial data cached
Splenomegaly	14	21.8 12.9–36.6ROR 22.0 · χ² 257 / p 5e-58	21.0 EB05 13.1 · IC025 +2.8 3/3 methods agree	Not in label — unassessed	serious PRR 16.2	no trial data cached
Apathy	15	18.8 11.4–31.1ROR 19.0 · χ² 235 / p 3e-53	18.1 EB05 11.2 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 18.0	no trial data cached
Salivary hypersecretion	10	18.2 9.8–33.8ROR 18.4 · χ² 146 / p 7e-34	16.9 EB05 8.7 · IC025 +2.2 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious PRR 14.7	no trial data cached
Malnutrition	11	18.0 10.0–32.4ROR 18.2 · χ² 160 / p 6e-37	16.9 EB05 9.1 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 12.4	no trial data cached
Seizure	110	17.4 14.6–20.8ROR 19.2 · χ² 1,695 / p <1e-300	17.4 EB05 14.8 · IC025 +3.7 3/3 methods agree	Not in label — unassessed	serious PRR 12.0	no trial data cached
Dystonia	16	14.9 9.2–24.3ROR 15.1 · χ² 195 / p 2e-44	14.1 EB05 8.6 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 10.9	no trial data cached
Convulsion (seizure)	43	13.5 10.1–18.1ROR 14.0 · χ² 485 / p 7e-108	13.2 EB05 10.1 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious PRR 9.2 · 95% clinician	no trial data cached
Respiratory tract infection	19	13.3 8.5–20.8ROR 13.5 · χ² 204 / p 1e-46	12.5 EB05 8.0 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 10.8	no trial data cached
Disease progression	85	13.1 10.7–16.1ROR 14.1 · χ² 943 / p 2e-207	13.0 EB05 10.8 · IC025 +3.3 3/3 methods agree	Reporting / coding artifact	serious PRR 10.0 · 92% clinician	no trial data cached
Dysphagia (difficulty swallowing)	66	12.7 10.0–16.0ROR 13.4 · χ² 701 / p 9e-155	12.5 EB05 10.1 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious PRR 11.6	no trial data cached
Respiratory failure	40	10.0 7.3–13.5ROR 10.3 · χ² 315 / p 1e-70	9.5 EB05 7.1 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 6.6	no trial data cached
Tremor (shaking)	78	8.5 6.9–10.6ROR 9.1 · χ² 515 / p 3e-114	8.3 EB05 6.8 · IC025 +2.6 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 8.1	no trial data cached
Dementia	10	6.5 3.5–12.1ROR 6.6 · χ² 41 / p 6e-11	5.2 EB05 3.0 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 4.2	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
Seizure	110	17.4 14.6–20.8ROR 19.2 · χ² 1,695 / p <1e-300	17.4 EB05 14.8 · IC025 +3.7 3/3 methods agree	Not in label — unassessed	serious PRR 12.0	no trial data cached
Disease progression	85	13.1 10.7–16.1ROR 14.1 · χ² 943 / p 2e-207	13.0 EB05 10.8 · IC025 +3.3 3/3 methods agree	Reporting / coding artifact	serious PRR 10.0 · 92% clinician	no trial data cached
Tremor (shaking)	78	8.5 6.9–10.6ROR 9.1 · χ² 515 / p 3e-114	8.3 EB05 6.8 · IC025 +2.6 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 8.1	no trial data cached
Dysphagia (difficulty swallowing)	66	12.7 10.0–16.0ROR 13.4 · χ² 701 / p 9e-155	12.5 EB05 10.1 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious PRR 11.6	no trial data cached
Epilepsy	44	26.2 19.6–35.1ROR 27.2 · χ² 1,043 / p 4e-229	25.9 EB05 20.1 · IC025 +3.9 3/3 methods agree	Not in label — unassessed	serious PRR 17.1 · 98% clinician	no trial data cached
Convulsion (seizure)	43	13.5 10.1–18.1ROR 14.0 · χ² 485 / p 7e-108	13.2 EB05 10.1 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious PRR 9.2 · 95% clinician	no trial data cached
Pneumonia aspiration	42	30.7 22.8–41.3ROR 31.8 · χ² 1,175 / p 7e-258	30.2 EB05 23.3 · IC025 +4.0 3/3 methods agree	Not in label — unassessed	serious PRR 20.4 · 90% clinician	no trial data cached
Respiratory failure	40	10.0 7.3–13.5ROR 10.3 · χ² 315 / p 1e-70	9.5 EB05 7.1 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 6.6	no trial data cached
Ataxia	25	38.2 25.9–56.3ROR 39.0 · χ² 867 / p 6e-191	37.1 EB05 26.4 · IC025 +3.8 3/3 methods agree	Not in label — unassessed	serious PRR 26.3 · 96% clinician	no trial data cached
Respiratory tract infection	19	13.3 8.5–20.8ROR 13.5 · χ² 204 / p 1e-46	12.5 EB05 8.0 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 10.8	no trial data cached
Motor dysfunction	17	30.6 19.1–49.0ROR 31.0 · χ² 457 / p 1e-101	29.6 EB05 19.6 · IC025 +3.2 3/3 methods agree	Not in label — unassessed	serious PRR 19.5	no trial data cached
Dystonia	16	14.9 9.2–24.3ROR 15.1 · χ² 195 / p 2e-44	14.1 EB05 8.6 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 10.9	no trial data cached
Apathy	15	18.8 11.4–31.1ROR 19.0 · χ² 235 / p 3e-53	18.1 EB05 11.2 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 18.0	no trial data cached
Aspiration	15	25.2 15.2–41.7ROR 25.5 · χ² 324 / p 8e-73	24.4 EB05 15.6 · IC025 +3.0 3/3 methods agree	Not in label — unassessed	serious PRR 16.0	no trial data cached
Splenomegaly	14	21.8 12.9–36.6ROR 22.0 · χ² 257 / p 5e-58	21.0 EB05 13.1 · IC025 +2.8 3/3 methods agree	Not in label — unassessed	serious PRR 16.2	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.

Ataxia — n=25, PRR 38.2
Pneumonia aspiration — n=42, PRR 30.7
Epilepsy — n=44, PRR 26.2
Seizure — n=110, PRR 17.4
Convulsion — n=43, PRR 13.5
Dysphagia — n=66, PRR 12.7
Respiratory failure — n=40, PRR 10.0

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 Miglustat?

In FDA FAERS, the most frequently co-reported reaction terms for Miglustat are seizure, tremor, dysphagia, epilepsy, convulsion, pneumonia aspiration. 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 Miglustat have an FDA boxed warning?

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

Do FAERS signals prove that Miglustat 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 2b371dfe-e2b0-47fe-b677-a7bde7149f87, effective 20251217; matched on openfda.generic_name.exact:"MIGLUSTAT")
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, 36 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.