Drug · FAERS side-effect profile with label screen

Abacavir and Lamivudine side effects: what 196 FDA adverse event reports show

Abacavir And Lamivudine · 6 reaction terms · 70 drug–reaction co-reports · data 2026-09-14

Drug class

Not stated in label

Label matched

Abacavir (Abacavir)

closest FDA label found for this product string; brand list suppressed because the label is a related product, not an exact match

Who reports

196 reports · 80% serious · 27 with death outcome · 47% female

openFDA FAERS counts, all years, deduplication not applied

Used for

Abacavir tablet, a nucleoside analogue human immunodeficiency virus (HIV-1) reverse transcriptase inhibitor, is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection. Abacavir tablets USP 300 mg, in combination with other antiretroviral agents, are indicated for the treatment of human immunodeficiency virus (HIV-1) infection.

FDA label, Indications and Usage

What it is

Abacavir sulfate is a synthetic carbocyclic nucleoside analogue with inhibitory activity against HIV-1.

FDA label, Description section

Boxed warning

HYPERSENSITIVITY REACTIONS WARNING: HYPERSENSITIVITY REACTIONS See full prescribing information for complete boxed warning. Serious and sometimes fatal hypersensitivity reactions have occurred with abacavir sulfate. ( 5.1 ) Hypersensitivity to abacavir is a multi-organ clinical syndrome.

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 4 strongest signals

Likely indication confounding 1Reporting / coding artifact 2Not in label — unassessed 1

What the badges mean

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. 2 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
Immunodeficiency	12	87.2 50.4–150.9ROR 92.8 · χ² 938 / p 2e-206	76.9 EB05 46.9 · IC025 +3.3 3/3 methods agree	Likely indication confounding term in indications	serious PRR 68.5	no trial data cached
Prescribed overdose	9	49.8 26.3–94.2ROR 52.1 · χ² 383 / p 1e-85	45.3 EB05 25.5 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 61.4	no trial data cached
Exposure during pregnancy	23	39.6 27.0–58.1ROR 44.7 · χ² 829 / p 1e-182	38.4 EB05 27.0 · IC025 +3.7 3/3 methods agree	Reporting / coding artifact	serious PRR 37.5 · ♀ 100% (drug 47%) · 91% clinician	no trial data cached
Foetal exposure during pregnancy	19	25.0 16.3–38.4ROR 27.6 · χ² 416 / p 9e-93	24.5 EB05 16.5 · IC025 +3.2 3/3 methods agree	Reporting / coding artifact	serious PRR 18.5	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
Exposure during pregnancy	23	39.6 27.0–58.1ROR 44.7 · χ² 829 / p 1e-182	38.4 EB05 27.0 · IC025 +3.7 3/3 methods agree	Reporting / coding artifact	serious PRR 37.5 · ♀ 100% (drug 47%) · 91% clinician	no trial data cached
Foetal exposure during pregnancy	19	25.0 16.3–38.4ROR 27.6 · χ² 416 / p 9e-93	24.5 EB05 16.5 · IC025 +3.2 3/3 methods agree	Reporting / coding artifact	serious PRR 18.5	no trial data cached
Immunodeficiency	12	87.2 50.4–150.9ROR 92.8 · χ² 938 / p 2e-206	76.9 EB05 46.9 · IC025 +3.3 3/3 methods agree	Likely indication confounding term in indications	serious PRR 68.5	no trial data cached
Prescribed overdose	9	49.8 26.3–94.2ROR 52.1 · χ² 383 / p 1e-85	45.3 EB05 25.5 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 61.4	no trial data cached
Coeliac disease	4	43.6 16.5–115.1ROR 44.5 · χ² 127 / p 1e-29	35.0 EB05 12.5 · IC025 +1.2 3/3 methods agree	Not in label — unassessed	serious PRR 39.3	no trial data cached
Helicobacter infection	3	31.5 10.2–96.8ROR 32.0 · χ² 61 / p 3e-15	20.9 EB05 4.0 · IC025 +0.5 3/3 methods agree	Not in label — unassessed	serious PRR 24.1	no trial data cached

Unlabeled candidate signals

Every screened signal with n ≥ 20 was either labeled, an indication term, or an artifact pattern — no unlabeled candidate stood out in the top signals.

✓ A hand-written Bradford Hill causality assessment exists for this drug: Abacavir ↔ Hypersensitivity reaction.

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 Abacavir and Lamivudine?

In FDA FAERS, the most frequently co-reported reaction terms for Abacavir and Lamivudine are immunodeficiency, prescribed overdose, coeliac disease, helicobacter infection. 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 Abacavir and Lamivudine have an FDA boxed warning?

Yes. The current FDA label carries a boxed warning: HYPERSENSITIVITY REACTIONS WARNING: HYPERSENSITIVITY REACTIONS See full prescribing information for complete boxed warning. Serious and sometimes fatal hypersensitivity reactions have occurred with abacavir sulfate. ( 5.1 ) Hypersensitivity to abacavir is a multi-organ clinical syndrome.

Do FAERS signals prove that Abacavir and Lamivudine 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 0d791375-e311-41f9-87b8-940657e6318c, effective 20201224; matched on openfda.generic_name.exact:"ABACAVIR")
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, 6 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.