Drug · FAERS side-effect profile with label screen
Efavirenz side effects: what 11,083 FDA adverse event reports show
Drug class
Human Immunodeficiency Virus 1 Non-Nucleoside Analog Reverse Transcriptase Inhibitor
FDA label (Established Pharmacologic Class) · compare the class
Who reports
11,083 reports · 97% serious · 1,540 with death outcome · 38% female
openFDA FAERS counts, all years, deduplication not applied
Used for
Efavirenz tablets in combination with other antiretroviral agents are indicated for the treatment of human immunodeficiency virus type 1 (HIV-1) infection in adults and in pediatric patients at least 3 months old and weighing at least 3.5 kg. Efavirenz.
FDA label, Indications and Usage
What it is
Efavirenz is an HIV-1 specific, non-nucleoside, reverse transcriptase inhibitor (NNRTI). Efavirenz is chemically described as (S)-6-chloro-4-(cyclopropylethynyl)-1,4-dihydro-4-(trifluoromethyl)-2H-3,1-benzoxazin-2-one.
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 1Labeled (related wording) 4Likely indication confounding 1Reporting / coding artifact 2Lab value / disease marker 2Not in label — unassessed 30
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. 996 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 |
|---|---|---|---|---|---|---|
| Paroxysmal extreme pain disorder | 17 | 3,965.0 1,711.5–9,185.7ROR 3,971.1 · χ² 20,308 / p <1e-300 | 521.1 EB05 344.6 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious n=17 | no trial data cached |
| Progressive external ophthalmoplegia | 72 | 2,356.9 1,665.9–3,334.6ROR 2,372.3 · χ² 73,882 / p <1e-300 | 814.6 EB05 668.6 · IC025 +6.6 3/3 methods agree | Not in label — unassessed | serious n=72 · ♀ 0% (drug 38%) · 100% clinician | no trial data cached |
| Ultrasound antenatal screen | 49 | 2,031.8 1,356.1–3,043.9ROR 2,040.8 · χ² 46,645 / p <1e-300 | 703.8 EB05 553.4 · IC025 +6.0 3/3 methods agree | Not in label — unassessed | serious n=49 · 100% clinician | no trial data cached |
| Hepatic displacement | 11 | 1,578.8 707.5–3,523.4ROR 1,580.4 · χ² 8,560 / p <1e-300 | 343.6 EB05 204.8 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=11 | no trial data cached |
| Diaphragmatic aplasia | 11 | 1,368.3 628.6–2,978.4ROR 1,369.7 · χ² 7,900 / p <1e-300 | 332.6 EB05 198.2 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=11 | no trial data cached |
| Pachygyria | 15 | 1,332.8 687.2–2,584.7ROR 1,334.6 · χ² 10,880 / p <1e-300 | 389.9 EB05 250.8 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=15 | no trial data cached |
| Hydranencephaly | 10 | 1,332.8 592.1–2,999.9ROR 1,334.0 · χ² 7,005 / p <1e-300 | 312.6 EB05 181.5 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Hiv-associated neurocognitive disorder | 39 | 1,010.7 684.8–1,491.6ROR 1,014.3 · χ² 24,866 / p <1e-300 | 495.6 EB05 378.3 · IC025 +5.6 3/3 methods agree | Not in label — unassessed | serious n=39 | no trial data cached |
| Spinocerebellar disorder | 15 | 874.6 473.8–1,614.6ROR 875.8 · χ² 8,327 / p <1e-300 | 338.4 EB05 217.7 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=15 | no trial data cached |
| Hiv viraemia | 58 | 731.2 540.1–990.1ROR 735.1 · χ² 29,865 / p <1e-300 | 447.7 EB05 359.1 · IC025 +6.1 3/3 methods agree | Not in label — unassessed | serious n=58 · 100% clinician | no trial data cached |
| Aids encephalopathy | 16 | 710.8 399.8–1,263.9ROR 711.8 · χ² 7,706 / p <1e-300 | 318.7 EB05 208.0 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=16 | no trial data cached |
| Cardiac malposition | 18 | 579.1 341.4–982.3ROR 580.0 · χ² 7,492 / p <1e-300 | 300.8 EB05 201.3 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious n=18 | no trial data cached |
| Tuberculoid leprosy | 14 | 512.2 283.6–925.0ROR 512.9 · χ² 5,210 / p <1e-300 | 259.7 EB05 164.4 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious n=14 | no trial data cached |
| Immune reconstitution syndrome | 278 | 512.1 449.0–584.0ROR 525.2 · χ² 110,870 / p <1e-300 | 391.2 EB05 354.1 · IC025 +7.7 3/3 methods agree | Labeled adverse reaction exact term | serious n=272 | no trial data cached |
| Viral mutation identified | 676 | 422.1 389.1–457.9ROR 449.5 · χ² 231,312 / p <1e-300 | 341.1 EB05 320.1 · IC025 +8.0 3/3 methods agree | Not in label — unassessed | serious n=675 · 97% clinician | no trial data cached |
| Virologic failure | 958 | 409.2 382.6–437.8ROR 447.9 · χ² 319,705 / p <1e-300 | 333.6 EB05 316.2 · IC025 +8.1 3/3 methods agree | Not in label — unassessed | serious n=955 · 98% clinician | no trial data cached |
| Immune reconstitution inflammatory syndrome associated tuberculosis | 57 | 391.0 294.1–519.9ROR 393.0 · χ² 18,011 / p <1e-300 | 291.8 EB05 233.6 · IC025 +6.0 3/3 methods agree | Labeled (related wording) related wording | serious n=57 · 96% clinician | no trial data cached |
| Birth mark | 32 | 339.3 232.9–494.2ROR 340.2 · χ² 8,848 / p <1e-300 | 245.2 EB05 181.9 · IC025 +5.1 3/3 methods agree | Not in label — unassessed | serious n=32 · ♀ 68% (drug 38%) · 97% clinician | no trial data cached |
| Isosporiasis | 11 | 306.3 162.0–579.4ROR 306.6 · χ² 2,619 / p <1e-300 | 181.1 EB05 107.9 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=11 | no trial data cached |
| Human immunodeficiency virus transmission | 33 | 274.9 190.8–396.0ROR 275.7 · χ² 7,612 / p <1e-300 | 210.6 EB05 156.9 · IC025 +5.1 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=33 · 100% clinician | no trial data cached |
| Mitochondrial toxicity | 101 | 265.1 215.4–326.2ROR 267.5 · χ² 23,035 / p <1e-300 | 222.5 EB05 188.4 · IC025 +6.4 3/3 methods agree | Not in label — unassessed | serious n=101 · ♀ 10% (drug 38%) · 96% clinician | no trial data cached |
| Trisomy 18 | 45 | 251.4 184.3–343.0ROR 252.4 · χ² 9,671 / p <1e-300 | 202.7 EB05 157.7 · IC025 +5.5 3/3 methods agree | Not in label — unassessed | serious n=45 · ♀ 15% (drug 38%) · 93% clinician | no trial data cached |
| Confusional arousal | 18 | 241.6 147.9–394.7ROR 242.0 · χ² 3,609 / p <1e-300 | 174.7 EB05 116.9 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious n=18 | no trial data cached |
| Secondary syphilis | 11 | 233.2 124.7–436.4ROR 233.5 · χ² 2,059 / p <1e-300 | 153.0 EB05 91.2 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=11 | no trial data cached |
| Lipodystrophy acquired | 230 | 228.8 199.7–262.0ROR 233.6 · χ² 46,262 / p <1e-300 | 200.5 EB05 179.7 · IC025 +6.9 3/3 methods agree | Not in label — unassessed | serious n=230 · 92% clinician | no trial data cached |
| Congenital umbilical hernia | 36 | 200.5 142.3–282.6ROR 201.2 · χ² 6,274 / p <1e-300 | 165.4 EB05 124.8 · IC025 +5.2 3/3 methods agree | Not in label — unassessed | serious n=36 · ♀ 61% (drug 38%) · 97% clinician | no trial data cached |
| Post procedural hypothyroidism | 18 | 179.6 110.8–291.2ROR 179.9 · χ² 2,756 / p <1e-300 | 139.9 EB05 93.6 · IC025 +4.1 3/3 methods agree | Reporting / coding artifact | serious n=18 | no trial data cached |
| Hydrops foetalis | 51 | 172.1 129.2–229.1ROR 172.9 · χ² 7,786 / p <1e-300 | 148.9 EB05 117.7 · IC025 +5.5 3/3 methods agree | Not in label — unassessed | serious n=51 · 92% clinician | no trial data cached |
| Tuberculoma of central nervous system | 15 | 168.6 99.4–285.9ROR 168.8 · χ² 2,141 / p <1e-300 | 129.6 EB05 83.4 · IC025 +3.8 3/3 methods agree | Labeled (related wording) related wording | serious n=15 | no trial data cached |
| Cd4 lymphocytes increased | 18 | 156.2 96.6–252.6ROR 156.5 · χ² 2,420 / p <1e-300 | 125.4 EB05 83.9 · IC025 +4.1 3/3 methods agree | Lab value / disease marker | serious n=18 | no trial data cached |
| Immune reconstitution inflammatory syndrome | 379 | 155.0 139.8–171.9ROR 160.5 · χ² 53,417 / p <1e-300 | 142.2 EB05 130.6 · IC025 +6.7 3/3 methods agree | Labeled (related wording) related wording | serious n=379 · 96% clinician | no trial data cached |
| Pathogen resistance | 641 | 143.4 132.6–155.0ROR 152.1 · χ² 84,064 / p <1e-300 | 132.7 EB05 124.3 · IC025 +6.8 3/3 methods agree | Reporting / coding artifact | serious PRR 83.3 · 98% clinician | no trial data cached |
| Meningoencephalitis viral | 12 | 134.9 75.1–242.3ROR 135.0 · χ² 1,365 / p 4e-299 | 105.3 EB05 64.2 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=12 | no trial data cached |
| Dysdiadochokinesis | 11 | 133.3 72.3–245.6ROR 133.4 · χ² 1,227 / p 4e-269 | 102.8 EB05 61.2 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=11 | no trial data cached |
| Deformity thorax | 12 | 124.4 69.4–223.1ROR 124.5 · χ² 1,264 / p 4e-277 | 98.8 EB05 60.2 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=12 | no trial data cached |
| Chronic respiratory disease | 18 | 102.7 63.9–165.0ROR 102.9 · χ² 1,623 / p <1e-300 | 88.5 EB05 59.2 · IC025 +4.0 3/3 methods agree | Labeled (related wording) related wording | serious n=18 | no trial data cached |
| Blood hiv rna increased | 91 | 101.1 82.0–124.8ROR 102.0 · χ² 8,464 / p <1e-300 | 94.1 EB05 79.0 · IC025 +5.6 3/3 methods agree | Lab value / disease marker | serious n=91 · 91% clinician | no trial data cached |
| Kaposi's sarcoma | 25 | 97.6 65.3–145.8ROR 97.8 · χ² 2,180 / p <1e-300 | 86.8 EB05 61.8 · IC025 +4.4 3/3 methods agree | Not in label — unassessed | serious n=25 · ♀ 0% (drug 38%) | no trial data cached |
| Meningitis tuberculous | 27 | 95.2 64.7–140.1ROR 95.5 · χ² 2,307 / p <1e-300 | 85.4 EB05 61.6 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious n=27 | no trial data cached |
| Encephalocele | 12 | 94.5 52.9–168.7ROR 94.6 · χ² 969 / p 4e-213 | 79.1 EB05 48.2 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=12 | 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 |
|---|---|---|---|---|---|---|
| Virologic failure | 958 | 409.2 382.6–437.8ROR 447.9 · χ² 319,705 / p <1e-300 | 333.6 EB05 316.2 · IC025 +8.1 3/3 methods agree | Not in label — unassessed | serious n=955 · 98% clinician | no trial data cached |
| Drug interaction | 760 | 9.1 8.5–9.7ROR 9.7 · χ² 5,487 / p <1e-300 | 9.0 EB05 8.5 · IC025 +3.1 3/3 methods agree | Reporting / coding artifact | serious PRR 5.9 | no trial data cached |
| Drug resistance | 742 | 56.3 52.4–60.4ROR 60.2 · χ² 39,094 / p <1e-300 | 54.6 EB05 51.4 · IC025 +5.6 3/3 methods agree | Reporting / coding artifact | serious PRR 36.3 · 95% clinician | no trial data cached |
| Viral mutation identified | 676 | 422.1 389.1–457.9ROR 449.5 · χ² 231,312 / p <1e-300 | 341.1 EB05 320.1 · IC025 +8.0 3/3 methods agree | Not in label — unassessed | serious n=675 · 97% clinician | no trial data cached |
| Pathogen resistance | 641 | 143.4 132.6–155.0ROR 152.1 · χ² 84,064 / p <1e-300 | 132.7 EB05 124.3 · IC025 +6.8 3/3 methods agree | Reporting / coding artifact | serious PRR 83.3 · 98% clinician | no trial data cached |
| Foetal exposure during pregnancy | 615 | 14.4 13.4–15.6ROR 15.2 · χ² 7,640 / p <1e-300 | 14.3 EB05 13.4 · IC025 +3.7 3/3 methods agree | Reporting / coding artifact | serious PRR 8.6 | no trial data cached |
| Depression | 461 | 3.8 3.5–4.2ROR 3.9 · χ² 966 / p 2e-212 | 3.8 EB05 3.5 · IC025 +1.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.1 · ♀ 10% (drug 38%) | no trial data cached |
| Maternal exposure during pregnancy | 426 | 9.2 8.4–10.1ROR 9.5 · χ² 3,093 / p <1e-300 | 9.1 EB05 8.4 · IC025 +3.0 3/3 methods agree | Reporting / coding artifact | serious PRR 6.4 · ♀ 99% (drug 38%) | no trial data cached |
| Treatment failure | 423 | 9.8 8.9–10.8ROR 10.1 · χ² 3,327 / p <1e-300 | 9.7 EB05 8.9 · IC025 +3.1 3/3 methods agree | Reporting / coding artifact | serious PRR 11.1 · 99% clinician | no trial data cached |
| Anaemia (low red blood cells) | 409 | 4.1 3.7–4.5ROR 4.2 · χ² 947 / p 3e-208 | 4.0 EB05 3.7 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 2.7 | no trial data cached |
| Pyrexia (fever) | 381 | 2.1 1.9–2.3ROR 2.1 · χ² 217 / p 2e-49 | 2.1 EB05 1.9 · IC025 +0.9 | Labeled (related wording) related wording | serious PRR 1.5 | no trial data cached |
| Immune reconstitution inflammatory syndrome | 379 | 155.0 139.8–171.9ROR 160.5 · χ² 53,417 / p <1e-300 | 142.2 EB05 130.6 · IC025 +6.7 3/3 methods agree | Labeled (related wording) related wording | serious n=379 · 96% clinician | no trial data cached |
| Vomiting | 348 | 1.4 1.3–1.6ROR 1.4 · χ² 41 / p 7e-11 | 1.4 EB05 1.3 · IC025 +0.3 | Labeled adverse reaction exact term | serious PRR 1.2 | no trial data cached |
| Death | 338 | 0.7 0.7–0.8ROR 0.7 · χ² 31 / p 1e-8 | 0.7 EB05 0.7 · IC025 -0.6 PRR-only: not supported by EBGM or IC | Outcome field, not a reaction | serious PRR 0.4 | no trial data cached |
| Diarrhoea (diarrhea) | 304 | 0.9 0.8–1.0ROR 0.9 · χ² 4 / p 0.025 | 0.9 EB05 0.8 · IC025 -0.4 PRR-only: not supported by EBGM or IC | Labeled adverse reaction exact term | serious PRR 0.9 | 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.
- Progressive external ophthalmoplegia — n=72, PRR 2,356.9
- Ultrasound antenatal screen — n=49, PRR 2,031.8
- Hiv-associated neurocognitive disorder — n=39, PRR 1,010.7
- Hiv viraemia — n=58, PRR 731.2
- Viral mutation identified — n=676, PRR 422.1
- Virologic failure — n=958, PRR 409.2
- Birth mark — n=32, PRR 339.3
- Mitochondrial toxicity — n=101, PRR 265.1
- Trisomy 18 — n=45, PRR 251.4
- Lipodystrophy acquired — n=230, PRR 228.8
✓ A hand-written Bradford Hill causality assessment exists for this drug: Efavirenz ↔ Depression / neuropsychiatric effects.
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 Efavirenz?
In FDA FAERS, the most frequently co-reported reaction terms for Efavirenz are virologic failure, viral mutation identified, depression, anaemia, pyrexia, immune reconstitution inflammatory syndrome. 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 Efavirenz have an FDA boxed warning?
No. The FDA label retrieved for Efavirenz has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Efavirenz 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 966b815d-1d78-4b54-8f00-c5a0b67c78be, effective 20230112; matched on
openfda.generic_name.exact:"EFAVIRENZ") - 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, 1,036 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.