Chlorothiazide side effects: what 917 FDA adverse event reports show
Brand names
Diuril
Who reports
917 reports · 81% serious · 137 with death outcome · 50% female
Used for
DIURIL is indicated as adjunctive therapy in edema associated with congestive heart failure, hepatic cirrhosis, and corticosteroid and estrogen therapy. DIURIL has also been found useful in edema due to various forms of renal dysfunction such as nephrotic syndrome, acute glomerulonephritis, and chronic renal failure.
What it is
DESCRIPTION DIURIL ® (chlorothiazide) is a diuretic and antihypertensive. It is 6-chloro-2 H -1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide.
Boxed warning
None in the current label
Causality screen of the 16 strongest signals
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.
- 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. 11 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Fluid overload | 19 | 29.5 18.9–46.0ROR 30.1 · χ² 494 / p 9e-110 | 28.7 EB05 19.4 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious PRR 25.6 | no trial data cached |
| Pulmonary hypertension | 25 | 27.4 18.6–40.3ROR 28.1 · χ² 609 / p 1e-134 | 26.8 EB05 19.1 · IC025 +3.5 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 19.6 · 92% clinician | no trial data cached |
| Pulmonary arterial hypertension | 15 | 23.6 14.3–38.9ROR 23.9 · χ² 302 / p 6e-68 | 22.9 EB05 14.6 · IC025 +2.9 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 17.2 | no trial data cached |
| Serotonin syndrome | 15 | 17.9 10.9–29.6ROR 18.2 · χ² 223 / p 8e-51 | 17.3 EB05 10.6 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 12.8 | no trial data cached |
| Aspiration | 8 | 16.9 8.5–33.7ROR 17.0 · χ² 104 / p 9e-25 | 14.7 EB05 6.5 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 10.8 | no trial data cached |
| Respiratory distress | 18 | 14.9 9.4–23.6ROR 15.2 · χ² 220 / p 4e-50 | 14.2 EB05 9.0 · IC025 +2.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 10.7 | no trial data cached |
| Respiratory failure | 42 | 13.2 9.8–17.7ROR 13.8 · χ² 461 / p 1e-102 | 12.9 EB05 9.8 · IC025 +3.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 9.3 · 93% clinician | no trial data cached |
| Shock | 13 | 13.0 7.6–22.4ROR 13.2 · χ² 133 / p 5e-31 | 11.7 EB05 6.5 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious PRR 9.3 | no trial data cached |
| Complication associated with device | 7 | 12.1 5.8–25.3ROR 12.2 · χ² 61 / p 3e-15 | 9.1 EB05 4.0 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 14.0 | no trial data cached |
| Scab | 6 | 12.1 5.5–26.9ROR 12.2 · χ² 51 / p 6e-13 | 8.5 EB05 3.6 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious n=6 | no trial data cached |
| Brain injury | 5 | 11.4 4.8–27.3ROR 11.5 · χ² 38 / p 4e-10 | 7.4 EB05 2.9 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 8.2 | no trial data cached |
| Petechiae | 5 | 11.0 4.6–26.4ROR 11.1 · χ² 36 / p 1e-9 | 7.1 EB05 2.9 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 9.4 | no trial data cached |
| Hypocalcaemia (low calcium) | 9 | 10.9 5.7–20.9ROR 11.0 · χ² 71 / p 1e-17 | 8.6 EB05 4.3 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 7.3 | no trial data cached |
| Joint range of motion decreased | 6 | 10.3 4.6–22.8ROR 10.3 · χ² 41 / p 6e-11 | 7.0 EB05 3.1 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 9.3 | no trial data cached |
| Cytokine release syndrome | 5 | 6.0 2.5–14.4ROR 6.0 · χ² 16 / p 3e-5 | 4.1 EB05 1.9 · IC025 +0.5 | Not in label — unassessed | serious PRR 4.3 | no trial data cached |
| Device dislocation | 9 | 4.7 2.5–9.1ROR 4.8 · χ² 23 / p 8e-7 | 3.9 EB05 2.2 · IC025 +0.8 3/3 methods agree | Reporting / coding artifact | serious PRR 3.4 | no trial data cached |
Trial evidence (ClinicalTrials.gov)
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 |
|---|---|---|---|---|---|---|
| Respiratory failure | 42 | 13.2 9.8–17.7ROR 13.8 · χ² 461 / p 1e-102 | 12.9 EB05 9.8 · IC025 +3.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 9.3 · 93% clinician | no trial data cached |
| Pulmonary hypertension | 25 | 27.4 18.6–40.3ROR 28.1 · χ² 609 / p 1e-134 | 26.8 EB05 19.1 · IC025 +3.5 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 19.6 · 92% clinician | no trial data cached |
| Fluid overload | 19 | 29.5 18.9–46.0ROR 30.1 · χ² 494 / p 9e-110 | 28.7 EB05 19.4 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious PRR 25.6 | no trial data cached |
| Respiratory distress | 18 | 14.9 9.4–23.6ROR 15.2 · χ² 220 / p 4e-50 | 14.2 EB05 9.0 · IC025 +2.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 10.7 | no trial data cached |
| Serotonin syndrome | 15 | 17.9 10.9–29.6ROR 18.2 · χ² 223 / p 8e-51 | 17.3 EB05 10.6 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 12.8 | no trial data cached |
| Pulmonary arterial hypertension | 15 | 23.6 14.3–38.9ROR 23.9 · χ² 302 / p 6e-68 | 22.9 EB05 14.6 · IC025 +2.9 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 17.2 | no trial data cached |
| Shock | 13 | 13.0 7.6–22.4ROR 13.2 · χ² 133 / p 5e-31 | 11.7 EB05 6.5 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious PRR 9.3 | no trial data cached |
| Device dislocation | 9 | 4.7 2.5–9.1ROR 4.8 · χ² 23 / p 8e-7 | 3.9 EB05 2.2 · IC025 +0.8 3/3 methods agree | Reporting / coding artifact | serious PRR 3.4 | no trial data cached |
| Hypocalcaemia (low calcium) | 9 | 10.9 5.7–20.9ROR 11.0 · χ² 71 / p 1e-17 | 8.6 EB05 4.3 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 7.3 | no trial data cached |
| Aspiration | 8 | 16.9 8.5–33.7ROR 17.0 · χ² 104 / p 9e-25 | 14.7 EB05 6.5 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 10.8 | no trial data cached |
| Complication associated with device | 7 | 12.1 5.8–25.3ROR 12.2 · χ² 61 / p 3e-15 | 9.1 EB05 4.0 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 14.0 | no trial data cached |
| Joint range of motion decreased | 6 | 10.3 4.6–22.8ROR 10.3 · χ² 41 / p 6e-11 | 7.0 EB05 3.1 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 9.3 | no trial data cached |
| Scab | 6 | 12.1 5.5–26.9ROR 12.2 · χ² 51 / p 6e-13 | 8.5 EB05 3.6 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious n=6 | no trial data cached |
| Cytokine release syndrome | 5 | 6.0 2.5–14.4ROR 6.0 · χ² 16 / p 3e-5 | 4.1 EB05 1.9 · IC025 +0.5 | Not in label — unassessed | serious PRR 4.3 | no trial data cached |
| Petechiae | 5 | 11.0 4.6–26.4ROR 11.1 · χ² 36 / p 1e-9 | 7.1 EB05 2.9 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 9.4 | 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 Chlorothiazide?
In FDA FAERS, the most frequently co-reported reaction terms for Chlorothiazide are respiratory failure, pulmonary hypertension, fluid overload, respiratory distress, serotonin syndrome, pulmonary arterial hypertension. 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 Chlorothiazide have an FDA boxed warning?
No. The FDA label retrieved for Chlorothiazide has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Chlorothiazide 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 bd936e35-1af8-42da-bcc0-f22489d68574, effective 20211101; matched on
openfda.generic_name.exact:"CHLOROTHIAZIDE") - 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, 27 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.