Drug · FAERS side-effect profile with label screen
Entecavir Anhydrous side effects: what 6,922 FDA adverse event reports show
Drug class
Hepatitis B Virus Nucleoside Analog Reverse Transcriptase Inhibitor
FDA label (Established Pharmacologic Class) · compare the class
Who reports
6,922 reports · 91% serious · 1,085 with death outcome · 35% female
openFDA FAERS counts, all years, deduplication not applied
Used for
Entecavir tablets are indicated for the treatment of chronic hepatitis B virus infection in adults and pediatric patients 2 years of age and older with evidence of active viral replication and either evidence of persistent elevations in serum aminotransferases (ALT or AST) or histologically active disease.
FDA label, Indications and Usage
What it is
Entecavir tablet USP, is a guanosine nucleoside analogue with selective activity against HBV.
FDA label, Description section
Boxed warning
SEVERE ACUTE EXACERBATIONS OF HEPATITIS B, PATIENTS CO-INFECTED WITH HIV AND HBV, AND LACTIC ACIDOSIS AND HEPATOMEGALY WARNING: SEVERE ACUTE EXACERBATIONS OF HEPATITIS B, PATIENTS CO-INFECTED WITH HIV AND HBV, and LA.
FDA 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 4Labeled (related wording) 7Likely indication confounding 1Reporting / coding artifact 1Lab value / disease marker 5Not in label — unassessed 22
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.
- 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.
- 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. 243 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 |
|---|---|---|---|---|---|---|
| Drug resistance | 353 | 42.2 38.1–46.7ROR 44.4 · χ² 13,977 / p <1e-300 | 41.5 EB05 38.0 · IC025 +5.1 3/3 methods agree | Reporting / coding artifact | serious PRR 29.6 | no trial data cached |
| Hepatic encephalopathy | 62 | 20.2 15.8–25.9ROR 20.4 · χ² 1,107 / p 4e-243 | 20.0 EB05 16.1 · IC025 +3.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 12.8 · 92% clinician | no trial data cached |
| Hepatic cirrhosis | 90 | 14.7 11.9–18.0ROR 14.8 · χ² 1,127 / p 3e-247 | 14.5 EB05 12.1 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious PRR 9.3 · ♀ 14% (drug 35%) | no trial data cached |
| Hepatic failure | 144 | 14.5 12.3–17.0ROR 14.8 · χ² 1,790 / p <1e-300 | 14.4 EB05 12.5 · IC025 +3.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 9.2 · 92% clinician | no trial data cached |
| Lymphocyte count decreased | 81 | 13.9 11.2–17.3ROR 14.1 · χ² 956 / p 4e-210 | 13.8 EB05 11.4 · IC025 +3.3 3/3 methods agree | Lab value / disease marker | serious PRR 10.8 · 99% clinician | no trial data cached |
| Ascites | 96 | 9.9 8.1–12.1ROR 10.0 · χ² 759 / p 2e-167 | 9.7 EB05 8.1 · IC025 +2.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.3 · ♀ 11% (drug 35%) | no trial data cached |
| Nephropathy toxic | 33 | 9.0 6.4–12.7ROR 9.0 · χ² 226 / p 2e-51 | 8.3 EB05 6.1 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 5.5 · ♀ 11% (drug 35%) · 94% clinician | no trial data cached |
| Cytokine release syndrome | 55 | 8.8 6.7–11.4ROR 8.8 · χ² 370 / p 1e-82 | 8.4 EB05 6.6 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 5.5 · 96% clinician | no trial data cached |
| Abortion induced | 27 | 8.7 6.0–12.7ROR 8.7 · χ² 176 / p 2e-40 | 7.9 EB05 5.6 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 5.8 · ♀ 100% (drug 35%) · 73% consumer | no trial data cached |
| Blood bilirubin increased | 76 | 8.5 6.8–10.7ROR 8.6 · χ² 496 / p 3e-110 | 8.2 EB05 6.7 · IC025 +2.6 3/3 methods agree | Lab value / disease marker | serious PRR 6.0 | no trial data cached |
| Covid-19 pneumonia | 33 | 8.4 6.0–11.9ROR 8.5 · χ² 208 / p 2e-47 | 7.8 EB05 5.7 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 5.3 · ♀ 14% (drug 35%) · 100% clinician | no trial data cached |
| Hypocalcaemia (low calcium) | 51 | 8.2 6.2–10.8ROR 8.3 · χ² 315 / p 1e-70 | 7.8 EB05 6.1 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious PRR 5.5 · 98% clinician | no trial data cached |
| Neutrophil count decreased | 108 | 8.1 6.7–9.8ROR 8.2 · χ² 664 / p 1e-146 | 7.9 EB05 6.7 · IC025 +2.6 3/3 methods agree | Lab value / disease marker | serious PRR 5.7 · 92% clinician | no trial data cached |
| Bacteraemia | 31 | 8.0 5.6–11.4ROR 8.0 · χ² 182 / p 7e-42 | 7.3 EB05 5.3 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious PRR 5.1 · 90% clinician | no trial data cached |
| Proteinuria | 49 | 7.9 6.0–10.4ROR 7.9 · χ² 287 / p 9e-65 | 7.5 EB05 5.8 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 5.3 | no trial data cached |
| Acute hepatic failure | 35 | 7.8 5.6–10.9ROR 7.8 · χ² 201 / p 7e-46 | 7.2 EB05 5.4 · IC025 +2.3 3/3 methods agree | Labeled (related wording) related wording | serious PRR 5.0 · 97% clinician | no trial data cached |
| Hepatic function abnormal | 91 | 7.5 6.1–9.1ROR 7.5 · χ² 502 / p 2e-111 | 7.2 EB05 6.0 · IC025 +2.5 3/3 methods agree | Labeled (related wording) related wording | serious PRR 5.0 · 92% clinician | no trial data cached |
| Febrile neutropenia | 161 | 7.4 6.3–8.6ROR 7.5 · χ² 882 / p 4e-194 | 7.2 EB05 6.3 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 4.7 · 97% clinician | no trial data cached |
| Glomerular filtration rate decreased | 29 | 7.3 5.1–10.5ROR 7.3 · χ² 150 / p 8e-35 | 6.6 EB05 4.8 · IC025 +2.1 3/3 methods agree | Lab value / disease marker | serious PRR 4.9 | no trial data cached |
| Transaminases increased | 51 | 7.0 5.3–9.2ROR 7.0 · χ² 254 / p 1e-57 | 6.6 EB05 5.2 · IC025 +2.3 3/3 methods agree | Labeled (related wording) related wording | serious PRR 4.7 | no trial data cached |
| Hypokalaemia (low potassium) | 99 | 6.5 5.4–8.0ROR 6.6 · χ² 460 / p 3e-102 | 6.4 EB05 5.4 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 4.2 · 98% clinician | no trial data cached |
| Jaundice (yellowing of skin/eyes) | 58 | 6.5 5.0–8.4ROR 6.6 · χ² 265 / p 6e-60 | 6.2 EB05 5.0 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious PRR 4.4 | no trial data cached |
| Alanine aminotransferase increased | 128 | 6.3 5.3–7.5ROR 6.4 · χ² 569 / p 6e-126 | 6.2 EB05 5.3 · IC025 +2.3 3/3 methods agree | Labeled (related wording) related wording | serious PRR 4.5 | no trial data cached |
| Metastases to lung | 24 | 6.3 4.2–9.4ROR 6.3 · χ² 102 / p 3e-24 | 5.7 EB05 4.0 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 4.0 · ♀ 14% (drug 35%) | no trial data cached |
| Platelet count decreased | 220 | 6.3 5.5–7.1ROR 6.4 · χ² 971 / p 1e-213 | 6.2 EB05 5.5 · IC025 +2.4 3/3 methods agree | Labeled (related wording) related wording | serious PRR 4.6 | no trial data cached |
| Viral infection | 68 | 6.2 4.9–7.9ROR 6.3 · χ² 292 / p 1e-65 | 6.0 EB05 4.9 · IC025 +2.2 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 5.5 | no trial data cached |
| Cytomegalovirus infection | 34 | 6.2 4.4–8.7ROR 6.2 · χ² 143 / p 3e-33 | 5.7 EB05 4.3 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 4.0 · 91% clinician | no trial data cached |
| Agranulocytosis (severe loss of white cells) | 37 | 6.1 4.4–8.4ROR 6.1 · χ² 152 / p 4e-35 | 5.7 EB05 4.3 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 3.9 · ♀ 63% (drug 35%) · 95% clinician | no trial data cached |
| Upper gastrointestinal haemorrhage | 33 | 5.9 4.2–8.3ROR 6.0 · χ² 130 / p 2e-30 | 5.5 EB05 4.1 · IC025 +1.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.8 · 100% clinician | no trial data cached |
| Neutrophil count increased | 20 | 5.9 3.8–9.1ROR 5.9 · χ² 76 / p 1e-18 | 5.2 EB05 3.6 · IC025 +1.6 3/3 methods agree | Lab value / disease marker | serious PRR 4.1 | no trial data cached |
| Drug-induced liver injury | 60 | 5.9 4.6–7.6ROR 5.9 · χ² 239 / p 3e-54 | 5.7 EB05 4.5 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 3.7 · 93% clinician | no trial data cached |
| Cholestasis (bile flow blockage) | 37 | 5.9 4.3–8.1ROR 5.9 · χ² 145 / p 1e-33 | 5.5 EB05 4.2 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 3.8 · 95% clinician | no trial data cached |
| Hyperbilirubinaemia | 19 | 5.6 3.6–8.8ROR 5.6 · χ² 67 / p 1e-16 | 5.0 EB05 3.4 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 3.6 | no trial data cached |
| Pneumocystis jirovecii pneumonia | 18 | 5.5 3.4–8.7ROR 5.5 · χ² 61 / p 3e-15 | 4.8 EB05 3.2 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 3.5 | no trial data cached |
| Septic shock | 76 | 5.3 4.3–6.7ROR 5.4 · χ² 263 / p 2e-59 | 5.2 EB05 4.3 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 3.4 · 96% clinician | no trial data cached |
| Blood creatinine increased | 114 | 5.3 4.4–6.3ROR 5.4 · χ² 392 / p 1e-87 | 5.2 EB05 4.4 · IC025 +2.1 3/3 methods agree | Labeled (related wording) related wording | serious PRR 3.7 | no trial data cached |
| Multiple organ dysfunction syndrome | 48 | 5.2 3.9–6.9ROR 5.2 · χ² 159 / p 8e-37 | 5.0 EB05 3.9 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 3.3 · 98% clinician | no trial data cached |
| Cytopenia | 20 | 5.1 3.3–7.9ROR 5.1 · χ² 61 / p 2e-15 | 4.6 EB05 3.1 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 3.3 · 100% clinician | no trial data cached |
| Aspartate aminotransferase increased | 88 | 5.0 4.1–6.2ROR 5.1 · χ² 280 / p 4e-63 | 4.9 EB05 4.1 · IC025 +1.9 3/3 methods agree | Labeled (related wording) related wording | serious PRR 3.5 | no trial data cached |
| Osteoporosis | 68 | 5.0 4.0–6.3ROR 5.0 · χ² 214 / p 8e-49 | 4.8 EB05 4.0 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 3.7 · 92% clinician | 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 |
|---|---|---|---|---|---|---|
| Off label use (used outside approved label) | 412 | 1.4 1.3–1.6ROR 1.5 · χ² 57 / p 2e-14 | 1.4 EB05 1.3 · IC025 +0.4 | Reporting / coding artifact | serious PRR 1.5 | no trial data cached |
| Drug resistance | 353 | 42.2 38.1–46.7ROR 44.4 · χ² 13,977 / p <1e-300 | 41.5 EB05 38.0 · IC025 +5.1 3/3 methods agree | Reporting / coding artifact | serious PRR 29.6 | no trial data cached |
| Death | 291 | 1.0 0.9–1.1ROR 1.0 · χ² 0 / p 0.354 | 1.0 EB05 0.9 · IC025 -0.2 PRR-only: not supported by EBGM or IC | Outcome field, not a reaction boxed warning mentions mortality | serious PRR 0.6 | no trial data cached |
| Pyrexia (fever) | 252 | 2.2 2.0–2.5ROR 2.3 · χ² 167 / p 1e-38 | 2.2 EB05 2.0 · IC025 +0.9 | Labeled adverse reaction exact term | serious PRR 1.7 | no trial data cached |
| Platelet count decreased | 220 | 6.3 5.5–7.1ROR 6.4 · χ² 971 / p 1e-213 | 6.2 EB05 5.5 · IC025 +2.4 3/3 methods agree | Labeled (related wording) related wording | serious PRR 4.6 | no trial data cached |
| Pneumonia (lung infection) | 211 | 2.0 1.7–2.3ROR 2.0 · χ² 103 / p 2e-24 | 2.0 EB05 1.8 · IC025 +0.8 | Labeled — boxed warning synonym match | serious PRR 1.3 | no trial data cached |
| Acute kidney injury (sudden kidney damage) | 161 | 3.2 2.8–3.7ROR 3.3 · χ² 243 / p 4e-55 | 3.2 EB05 2.8 · IC025 +1.4 3/3 methods agree | Labeled (related wording) related wording | serious PRR 2.0 · 96% clinician | no trial data cached |
| Febrile neutropenia | 161 | 7.4 6.3–8.6ROR 7.5 · χ² 882 / p 4e-194 | 7.2 EB05 6.3 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 4.7 · 97% clinician | no trial data cached |
| White blood cell count decreased | 159 | 4.4 3.8–5.2ROR 4.5 · χ² 422 / p 4e-94 | 4.4 EB05 3.8 · IC025 +1.9 3/3 methods agree | Lab value / disease marker | serious PRR 3.6 | no trial data cached |
| Neutropenia (low neutrophils (infection-fighting cells)) | 157 | 3.5 3.0–4.1ROR 3.6 · χ² 281 / p 2e-63 | 3.5 EB05 3.0 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 2.2 · 96% clinician | no trial data cached |
| Anaemia (low red blood cells) | 156 | 2.5 2.1–2.9ROR 2.5 · χ² 137 / p 6e-32 | 2.5 EB05 2.2 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 1.7 · 93% clinician | no trial data cached |
| Thrombocytopenia (low platelets) | 148 | 4.0 3.4–4.7ROR 4.1 · χ² 335 / p 5e-75 | 4.0 EB05 3.5 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 2.6 · 96% clinician | no trial data cached |
| Hepatic failure | 144 | 14.5 12.3–17.0ROR 14.8 · χ² 1,790 / p <1e-300 | 14.4 EB05 12.5 · IC025 +3.5 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 9.2 · 92% clinician | no trial data cached |
| Decreased appetite (loss of appetite) | 131 | 1.7 1.4–2.0ROR 1.7 · χ² 39 / p 3e-10 | 1.7 EB05 1.5 · IC025 +0.5 | Not in label — unassessed | serious PRR 1.4 | no trial data cached |
| Renal impairment | 131 | 4.7 4.0–5.6ROR 4.8 · χ² 385 / p 6e-86 | 4.7 EB05 4.0 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 3.1 | 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.
- Hepatic cirrhosis — n=90, PRR 14.7
- Nephropathy toxic — n=33, PRR 9.0
- Cytokine release syndrome — n=55, PRR 8.8
- Abortion induced — n=27, PRR 8.7
- Covid-19 pneumonia — n=33, PRR 8.4
- Hypocalcaemia — n=51, PRR 8.2
- Bacteraemia — n=31, PRR 8.0
- Proteinuria — n=49, PRR 7.9
- Febrile neutropenia — n=161, PRR 7.4
- Hypokalaemia — n=99, PRR 6.5
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 Entecavir?
In FDA FAERS, the most frequently co-reported reaction terms for Entecavir are pyrexia, platelet count decreased, pneumonia, acute kidney injury, febrile neutropenia, white blood cell count decreased. 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 Entecavir have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: SEVERE ACUTE EXACERBATIONS OF HEPATITIS B, PATIENTS CO-INFECTED WITH HIV AND HBV, AND LACTIC ACIDOSIS AND HEPATOMEGALY WARNING: SEVERE ACUTE EXACERBATIONS OF HEPATITIS B, PATIENTS CO-INFECTED WITH HIV AND HBV, and LA.
Do FAERS signals prove that Entecavir 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 01ec50a1-6c6c-46f0-8c74-73542b0a59c3, effective 20250109; matched on
openfda.generic_name.exact:"ENTECAVIR") - 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, 283 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.