Nitazoxanide side effects: what 343 FDA adverse event reports show

Nitazoxanide · 7 reaction terms · 80 drug–reaction co-reports · data 2026-09-14

Drug class

Antiprotozoal

FDA label (Established Pharmacologic Class)

Who reports

343 reports · 92% serious · 71 with death outcome · 38% female

openFDA FAERS counts, all years, deduplication not applied

Used for

Diarrhea caused by Giardia lamblia or Cryptosporidium parvum: Nitazoxanide tablets (patients 12 years and older) are indicated for the treatment of diarrhea caused by Giardia lamblia or Cryptosporidium parvum. Limitations of Use Nitazoxanide tablets ha.

FDA label, Indications and Usage

What it is

Nitazoxanide tablets contain the active ingredient, nitazoxanide, a synthetic antiprotozoal for oral administration. Nitazoxanide is a pale yellow to yellow crystalline powder. It is poorly soluble in ethanol and practically insoluble in water.

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 4 strongest signals

Reporting / coding artifact 1Not in label — unassessed 3

What the badges mean

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. 3 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
Lymphopenia	8	34.8 17.5–69.0ROR 35.6 · χ² 230 / p 3e-52	32.2 EB05 17.3 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 23.5	no trial data cached
Serotonin syndrome	10	32.0 17.4–58.9ROR 32.9 · χ² 270 / p 6e-61	30.2 EB05 17.4 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 20.1	no trial data cached
Disease progression	46	23.9 18.2–31.2ROR 27.4 · χ² 990 / p 2e-217	23.6 EB05 18.4 · IC025 +3.8 3/3 methods agree	Reporting / coding artifact	serious PRR 16.9 · ♀ 7% (drug 38%)	no trial data cached
Cytomegalovirus infection	5	18.4 7.7–43.9ROR 18.6 · χ² 66 / p 3e-16	14.0 EB05 4.5 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 11.6	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
Disease progression	46	23.9 18.2–31.2ROR 27.4 · χ² 990 / p 2e-217	23.6 EB05 18.4 · IC025 +3.8 3/3 methods agree	Reporting / coding artifact	serious PRR 16.9 · ♀ 7% (drug 38%)	no trial data cached
Serotonin syndrome	10	32.0 17.4–58.9ROR 32.9 · χ² 270 / p 6e-61	30.2 EB05 17.4 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 20.1	no trial data cached
Lymphopenia	8	34.8 17.5–69.0ROR 35.6 · χ² 230 / p 3e-52	32.2 EB05 17.3 · IC025 +2.3 3/3 methods agree	Not in label — unassessed	serious PRR 23.5	no trial data cached
Cytomegalovirus infection	5	18.4 7.7–43.9ROR 18.6 · χ² 66 / p 3e-16	14.0 EB05 4.5 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 11.6	no trial data cached
Mydriasis	4	19.1 7.2–50.6ROR 19.3 · χ² 52 / p 3e-13	13.1 EB05 3.6 · IC025 +0.9 3/3 methods agree	Not in label — unassessed	serious PRR 15.4	no trial data cached
Haematotoxicity	4	26.4 10.0–69.9ROR 26.7 · χ² 74 / p 4e-18	20.2 EB05 5.3 · IC025 +1.0 3/3 methods agree	Not in label — unassessed	serious PRR 16.9	no trial data cached
Helicobacter infection	3	18.0 5.8–55.5ROR 18.1 · χ² 33 / p 5e-9	9.9 EB05 2.5 · IC025 +0.3 3/3 methods agree	Not in label — unassessed	serious PRR 7.9	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.

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 Nitazoxanide?

In FDA FAERS, the most frequently co-reported reaction terms for Nitazoxanide are serotonin syndrome, lymphopenia, cytomegalovirus infection, mydriasis, haematotoxicity, 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 Nitazoxanide have an FDA boxed warning?

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

Do FAERS signals prove that Nitazoxanide 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 c0dc0656-3c46-43f9-adea-5285c522cef8, effective 20251009; matched on openfda.generic_name.exact:"NITAZOXANIDE")
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, 7 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.