Drug · FAERS side-effect profile with label screen
Burosumab side effects: what 6,315 FDA adverse event reports show
Drug class
Fibroblast growth factor 23 (fgf23) blocking antibody
FDA label, Indications wording
Brand names
Crysvita
openFDA label
Who reports
6,315 reports · 22% serious · 42 with death outcome · 55% female
openFDA FAERS counts, all years, deduplication not applied
Used for
CRYSVITA is a fibroblast growth factor 23 (FGF23) blocking antibody indicated for: The treatment of X-linked hypophosphatemia (XLH) in adult and pediatric patients 6 months of age and older. ( 1.1 ) The treatment of FGF23-related hypophosphatemia in tu.
FDA label, Indications and Usage
What it is
Burosumab-twza is a human immunoglobulin G subclass 1 (IgG1), anti-human fibroblast growth factor 23 (FGF23) antibody produced by recombinant DNA technology using Chinese hamster ovary cells. Burosumab-twza is composed of two heavy chain (γ1-chain) molecules and two light chain (κ-chain) molecules.
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 14Labeled (related wording) 5Reporting / coding artifact 10Lab value / disease marker 2Not in label — unassessed 9
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.
- Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
- 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. 90 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
Show:
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Restless legs syndrome | 276 | 51.1 45.5–57.4ROR 53.4 · χ² 13,312 / p <1e-300 | 50.2 EB05 45.4 · IC025 +5.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 35.8 | no trial data cached |
| Tooth abscess | 121 | 39.8 33.3–47.5ROR 40.5 · χ² 4,483 / p <1e-300 | 39.1 EB05 33.6 · IC025 +4.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 52.6 | no trial data cached |
| Contraindicated product administered | 190 | 21.0 18.3–24.2ROR 21.7 · χ² 3,589 / p <1e-300 | 20.9 EB05 18.5 · IC025 +4.1 3/3 methods agree | Reporting / coding artifact | serious PRR 16.9 | no trial data cached |
| Inappropriate schedule of product administration | 708 | 13.3 12.5–14.3ROR 14.9 · χ² 8,110 / p <1e-300 | 13.3 EB05 12.5 · IC025 +3.6 3/3 methods agree | Reporting / coding artifact | serious PRR 10.6 | no trial data cached |
| Incorrect route of product administration | 65 | 12.9 10.1–16.4ROR 13.0 · χ² 699 / p 3e-154 | 12.7 EB05 10.2 · IC025 +3.1 3/3 methods agree | Reporting / coding artifact | serious PRR 11.6 | no trial data cached |
| Bone pain | 209 | 11.9 10.4–13.6ROR 12.2 · χ² 2,069 / p <1e-300 | 11.8 EB05 10.5 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious PRR 12.1 | no trial data cached |
| Dental caries | 35 | 10.5 7.6–14.7ROR 10.6 · χ² 292 / p 8e-66 | 10.0 EB05 7.3 · IC025 +2.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 9.9 | no trial data cached |
| Toothache | 52 | 9.6 7.3–12.5ROR 9.6 · χ² 390 / p 5e-87 | 9.2 EB05 7.2 · IC025 +2.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 9.3 | no trial data cached |
| Pharyngitis streptococcal | 31 | 9.5 6.7–13.5ROR 9.6 · χ² 228 / p 9e-52 | 8.8 EB05 6.4 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | – | no trial data cached |
| Knee operation | 26 | 8.9 6.1–13.1ROR 8.9 · χ² 174 / p 4e-40 | 8.1 EB05 5.7 · IC025 +2.3 3/3 methods agree | Reporting / coding artifact | serious PRR 19.3 | no trial data cached |
| Therapy interrupted | 180 | 8.7 7.5–10.0ROR 8.9 · χ² 1,217 / p 7e-267 | 8.5 EB05 7.5 · IC025 +2.8 3/3 methods agree | Reporting / coding artifact | serious PRR 5.9 | no trial data cached |
| Injection site pruritus | 157 | 7.8 6.7–9.2ROR 8.0 · χ² 932 / p 5e-205 | 7.7 EB05 6.7 · IC025 +2.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 10.4 | no trial data cached |
| Injection site urticaria | 57 | 7.8 6.0–10.1ROR 7.9 · χ² 332 / p 2e-74 | 7.4 EB05 5.9 · IC025 +2.4 3/3 methods agree | Labeled adverse reaction exact term | serious n=3 | no trial data cached |
| Product dose omission issue | 645 | 7.5 7.0–8.1ROR 8.3 · χ² 3,692 / p <1e-300 | 7.5 EB05 7.0 · IC025 +2.8 3/3 methods agree | Reporting / coding artifact | serious PRR 8.1 | no trial data cached |
| Product dose omission | 140 | 7.0 6.0–8.3ROR 7.2 · χ² 719 / p 1e-158 | 6.9 EB05 6.0 · IC025 +2.5 3/3 methods agree | Reporting / coding artifact | serious PRR 4.4 · 90% clinician | no trial data cached |
| Blood alkaline phosphatase increased | 51 | 6.8 5.2–9.0ROR 6.9 · χ² 247 / p 5e-56 | 6.5 EB05 5.1 · IC025 +2.2 3/3 methods agree | Lab value / disease marker | serious PRR 6.6 | no trial data cached |
| Ear infection | 53 | 6.6 5.1–8.7ROR 6.7 · χ² 248 / p 3e-56 | 6.3 EB05 5.0 · IC025 +2.2 3/3 methods agree | Labeled (related wording) related wording | serious PRR 4.3 | no trial data cached |
| Sars-cov-2 test positive | 26 | 6.5 4.4–9.5ROR 6.5 · χ² 115 / p 4e-27 | 5.9 EB05 4.2 · IC025 +1.9 3/3 methods agree | Lab value / disease marker | serious n=2 | no trial data cached |
| Tooth fracture | 21 | 6.3 4.1–9.7ROR 6.4 · χ² 89 / p 2e-21 | 5.6 EB05 3.9 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 11.0 | no trial data cached |
| Tooth infection | 25 | 6.3 4.3–9.3ROR 6.3 · χ² 106 / p 3e-25 | 5.7 EB05 4.0 · IC025 +1.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 7.8 | no trial data cached |
| Insurance issue | 28 | 6.3 4.3–9.1ROR 6.3 · χ² 119 / p 6e-28 | 5.7 EB05 4.1 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 4.9 · 96% clinician | no trial data cached |
| Spinal pain | 21 | 6.0 3.9–9.1ROR 6.0 · χ² 82 / p 8e-20 | 5.3 EB05 3.7 · IC025 +1.7 3/3 methods agree | Labeled (related wording) related wording | serious PRR 11.9 | no trial data cached |
| Hypercalcaemia | 22 | 5.9 3.9–9.0ROR 5.9 · χ² 85 / p 1e-20 | 5.3 EB05 3.7 · IC025 +1.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 8.5 · 95% clinician | no trial data cached |
| Vitamin d deficiency | 17 | 5.8 3.6–9.3ROR 5.8 · χ² 63 / p 1e-15 | 5.1 EB05 3.3 · IC025 +1.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.5 | no trial data cached |
| Injection site rash | 48 | 5.3 4.0–7.0ROR 5.3 · χ² 161 / p 3e-37 | 5.0 EB05 3.9 · IC025 +1.9 3/3 methods agree | Labeled adverse reaction exact term | serious n=2 | no trial data cached |
| Injection site mass | 58 | 5.2 4.0–6.8ROR 5.3 · χ² 194 / p 2e-44 | 5.0 EB05 4.0 · IC025 +1.9 3/3 methods agree | Labeled (related wording) related wording | serious PRR 3.8 | no trial data cached |
| Laboratory test abnormal | 46 | 5.2 3.9–6.9ROR 5.2 · χ² 151 / p 4e-35 | 4.9 EB05 3.9 · IC025 +1.8 3/3 methods agree | Reporting / coding artifact | serious PRR 4.3 | no trial data cached |
| Gastroenteritis viral | 27 | 5.0 3.4–7.2ROR 5.0 · χ² 81 / p 1e-19 | 4.6 EB05 3.3 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 2.8 | no trial data cached |
| Tooth extraction | 18 | 4.8 3.0–7.6ROR 4.8 · χ² 50 / p 6e-13 | 4.3 EB05 2.9 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 7.8 | no trial data cached |
| Joint stiffness | 37 | 4.7 3.4–6.5ROR 4.7 · χ² 104 / p 1e-24 | 4.4 EB05 3.4 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 8.6 | no trial data cached |
| Foot deformity | 15 | 4.5 2.7–7.4ROR 4.5 · χ² 37 / p 5e-10 | 4.0 EB05 2.6 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 6.5 | no trial data cached |
| Tooth disorder | 30 | 4.5 3.1–6.4ROR 4.5 · χ² 77 / p 8e-19 | 4.2 EB05 3.1 · IC025 +1.5 3/3 methods agree | Labeled (related wording) related wording | serious PRR 5.5 · 90% clinician | no trial data cached |
| Joint dislocation | 14 | 4.4 2.6–7.5ROR 4.4 · χ² 34 / p 3e-9 | 3.9 EB05 2.5 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 7.6 | no trial data cached |
| Spinal operation | 16 | 4.4 2.7–7.2ROR 4.4 · χ² 39 / p 3e-10 | 3.9 EB05 2.6 · IC025 +1.2 3/3 methods agree | Reporting / coding artifact | serious PRR 7.2 | no trial data cached |
| Illness | 123 | 4.1 3.4–4.8ROR 4.1 · χ² 283 / p 1e-63 | 4.0 EB05 3.4 · IC025 +1.7 3/3 methods agree | Reporting / coding artifact | serious PRR 3.6 | no trial data cached |
| Pain in extremity | 353 | 4.0 3.6–4.4ROR 4.2 · χ² 793 / p 8e-175 | 4.0 EB05 3.6 · IC025 +1.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.5 | no trial data cached |
| Injection site reaction | 82 | 4.0 3.2–4.9ROR 4.0 · χ² 180 / p 3e-41 | 3.9 EB05 3.2 · IC025 +1.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.4 | no trial data cached |
| Injection site irritation | 15 | 3.9 2.4–6.5ROR 3.9 · χ² 30 / p 2e-8 | 3.6 EB05 2.3 · IC025 +1.0 3/3 methods agree | Labeled (related wording) related wording | serious n=2 | no trial data cached |
| Injection site erythema (redness where injected) | 144 | 3.9 3.3–4.6ROR 3.9 · χ² 306 / p 8e-69 | 3.8 EB05 3.3 · IC025 +1.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.0 | no trial data cached |
| Injection site swelling | 87 | 3.8 3.1–4.7ROR 3.9 · χ² 178 / p 5e-41 | 3.7 EB05 3.1 · IC025 +1.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.0 | 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 |
|---|---|---|---|---|---|---|
| Inappropriate schedule of product administration | 708 | 13.3 12.5–14.3ROR 14.9 · χ² 8,110 / p <1e-300 | 13.3 EB05 12.5 · IC025 +3.6 3/3 methods agree | Reporting / coding artifact | serious PRR 10.6 | no trial data cached |
| Product dose omission issue | 645 | 7.5 7.0–8.1ROR 8.3 · χ² 3,692 / p <1e-300 | 7.5 EB05 7.0 · IC025 +2.8 3/3 methods agree | Reporting / coding artifact | serious PRR 8.1 | no trial data cached |
| Pain | 391 | 2.1 1.9–2.3ROR 2.2 · χ² 234 / p 4e-53 | 2.1 EB05 1.9 · IC025 +0.9 | Labeled adverse reaction exact term | serious PRR 1.7 | no trial data cached |
| Arthralgia (joint pain) | 376 | 3.0 2.7–3.3ROR 3.1 · χ² 514 / p 4e-114 | 3.0 EB05 2.8 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 3.8 | no trial data cached |
| Pain in extremity | 353 | 4.0 3.6–4.4ROR 4.2 · χ² 793 / p 8e-175 | 4.0 EB05 3.6 · IC025 +1.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.5 | no trial data cached |
| Restless legs syndrome | 276 | 51.1 45.5–57.4ROR 53.4 · χ² 13,312 / p <1e-300 | 50.2 EB05 45.4 · IC025 +5.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 35.8 | no trial data cached |
| Incorrect dose administered | 252 | 3.7 3.3–4.2ROR 3.8 · χ² 504 / p 6e-112 | 3.7 EB05 3.3 · IC025 +1.7 3/3 methods agree | Reporting / coding artifact | serious PRR 5.4 | no trial data cached |
| Injection site pain (pain where injected) | 243 | 2.7 2.4–3.0ROR 2.7 · χ² 253 / p 2e-57 | 2.6 EB05 2.4 · IC025 +1.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.4 | no trial data cached |
| Bone pain | 209 | 11.9 10.4–13.6ROR 12.2 · χ² 2,069 / p <1e-300 | 11.8 EB05 10.5 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious PRR 12.1 | no trial data cached |
| Contraindicated product administered | 190 | 21.0 18.3–24.2ROR 21.7 · χ² 3,589 / p <1e-300 | 20.9 EB05 18.5 · IC025 +4.1 3/3 methods agree | Reporting / coding artifact | serious PRR 16.9 | no trial data cached |
| Back pain | 189 | 2.7 2.3–3.1ROR 2.8 · χ² 203 / p 3e-46 | 2.7 EB05 2.4 · IC025 +1.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.0 | no trial data cached |
| Therapy interrupted | 180 | 8.7 7.5–10.0ROR 8.9 · χ² 1,217 / p 7e-267 | 8.5 EB05 7.5 · IC025 +2.8 3/3 methods agree | Reporting / coding artifact | serious PRR 5.9 | no trial data cached |
| Covid-19 | 179 | 3.4 2.9–3.9ROR 3.4 · χ² 297 / p 8e-67 | 3.3 EB05 2.9 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 3.6 | no trial data cached |
| Injection site pruritus | 157 | 7.8 6.7–9.2ROR 8.0 · χ² 932 / p 5e-205 | 7.7 EB05 6.7 · IC025 +2.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 10.4 | no trial data cached |
| Injection site erythema (redness where injected) | 144 | 3.9 3.3–4.6ROR 3.9 · χ² 306 / p 8e-69 | 3.8 EB05 3.3 · IC025 +1.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.0 | 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.
- Bone pain — n=209, PRR 11.9
- Pharyngitis streptococcal — n=31, PRR 9.5
- Tooth fracture — n=21, PRR 6.3
- Insurance issue — n=28, PRR 6.3
- Gastroenteritis viral — n=27, PRR 5.0
- Joint stiffness — n=37, PRR 4.7
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 Burosumab?
In FDA FAERS, the most frequently co-reported reaction terms for Burosumab are pain, arthralgia, pain in extremity, restless legs syndrome, injection site pain, bone pain. 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 Burosumab have an FDA boxed warning?
No. The FDA label retrieved for Burosumab has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Burosumab 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 102f96a0-6e3a-4fc1-b204-34d604683af6, effective 20260422; matched on
openfda.generic_name.exact:"BUROSUMAB") - 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, fieldpatient.drug.openfda.generic_name.exact, 130 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.