Drug · FAERS side-effect profile with label screen
Chlorthalidone side effects: what 11,542 FDA adverse event reports show
Who reports
11,542 reports · 63% serious · 690 with death outcome · 56% female
openFDA FAERS counts, all years, deduplication not applied
Used for
Diuretics such as chlorthalidone are indicated in the management of hypertension either as the sole therapeutic agent or to enhance the effect of other antihypertensive drugs in the more severe forms of hypertension. Chlorthalidone is indicated as adjunctive therapy in edema associated with congestive heart failure, hepatic cirrhosis, and corticosteroid and estrogen therapy.
FDA label, Indications and Usage
What it is
DESCRIPTION Chlorthalidone is an oral antihypertensive/diuretic. It is a monosulfamyl diuretic that differs chemically from thiazide diuretics in that a double-ring system is incorporated in its structure.
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 2Lab value / disease marker 3Not 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.
- 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. 1,069 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 |
|---|---|---|---|---|---|---|
| Lichen planopilaris | 19 | 347.3 212.6–567.5ROR 347.9 · χ² 5,209 / p <1e-300 | 225.3 EB05 152.5 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious n=19 | no trial data cached |
| Hemihypoaesthesia | 18 | 103.4 64.3–166.2ROR 103.5 · χ² 1,630 / p <1e-300 | 88.8 EB05 59.4 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=18 | no trial data cached |
| Hemiparaesthesia | 19 | 94.0 59.3–149.1ROR 94.2 · χ² 1,574 / p <1e-300 | 82.2 EB05 55.6 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=19 | no trial data cached |
| Renin increased | 12 | 83.0 46.5–148.0ROR 83.1 · χ² 852 / p 1e-187 | 70.8 EB05 43.2 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=12 | no trial data cached |
| Spinal cord abscess | 11 | 75.5 41.3–138.0ROR 75.6 · χ² 706 / p 7e-156 | 64.7 EB05 38.6 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious n=11 | no trial data cached |
| Milk-alkali syndrome | 19 | 67.8 42.9–107.2ROR 67.9 · χ² 1,141 / p 2e-250 | 61.5 EB05 41.6 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious n=19 | no trial data cached |
| Chronic kidney disease-mineral and bone disorder | 32 | 55.7 39.2–79.1ROR 55.8 · χ² 1,613 / p <1e-300 | 52.4 EB05 38.9 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious n=32 | no trial data cached |
| Diarrhoea infectious | 15 | 35.7 21.4–59.5ROR 35.7 · χ² 462 / p 7e-103 | 33.7 EB05 21.6 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=15 | no trial data cached |
| Nephrogenic anaemia | 88 | 34.8 28.2–43.0ROR 35.1 · χ² 2,804 / p <1e-300 | 34.0 EB05 28.4 · IC025 +4.5 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=88 | no trial data cached |
| Choroidal effusion | 14 | 32.4 19.1–54.9ROR 32.4 · χ² 388 / p 1e-86 | 30.6 EB05 19.4 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=14 | no trial data cached |
| Hyperparathyroidism secondary | 43 | 31.4 23.2–42.4ROR 31.5 · χ² 1,213 / p 5e-266 | 30.5 EB05 23.6 · IC025 +4.0 3/3 methods agree | Labeled (related wording) related wording | serious n=43 | no trial data cached |
| Allergy to animal | 17 | 29.9 18.5–48.3ROR 29.9 · χ² 439 / p 9e-98 | 28.6 EB05 18.9 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=16 | no trial data cached |
| Pneumonia viral | 43 | 24.8 18.4–33.5ROR 24.9 · χ² 947 / p 3e-208 | 24.3 EB05 18.8 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious n=43 · ♀ 100% (drug 56%) · 91% clinician | no trial data cached |
| Renal artery stenosis | 17 | 22.5 14.0–36.4ROR 22.6 · χ² 325 / p 7e-73 | 21.7 EB05 14.2 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=17 | no trial data cached |
| Hyperglycaemic hyperosmolar nonketotic syndrome | 13 | 21.6 12.5–37.3ROR 21.6 · χ² 232 / p 1e-52 | 20.6 EB05 12.4 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious n=13 | no trial data cached |
| Rebound acid hypersecretion | 36 | 21.6 15.5–29.9ROR 21.6 · χ² 677 / p 1e-149 | 21.1 EB05 15.9 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=36 | no trial data cached |
| Meningitis aseptic | 43 | 17.6 13.1–23.8ROR 17.7 · χ² 651 / p 6e-144 | 17.3 EB05 13.3 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=43 · ♀ 0% (drug 56%) · 100% clinician | no trial data cached |
| Metabolic alkalosis | 15 | 17.2 10.4–28.7ROR 17.3 · χ² 211 / p 3e-48 | 16.4 EB05 10.0 · IC025 +2.6 3/3 methods agree | Labeled (related wording) related wording | serious n=15 | no trial data cached |
| Aortic dilatation | 10 | 16.8 9.0–31.3ROR 16.8 · χ² 132 / p 8e-31 | 15.2 EB05 7.6 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Blood pressure systolic abnormal | 22 | 16.2 10.6–24.6ROR 16.2 · χ² 296 / p 1e-66 | 15.6 EB05 10.6 · IC025 +2.9 3/3 methods agree | Lab value / disease marker | serious n=21 · 100% clinician | no trial data cached |
| Breath sounds abnormal | 42 | 15.6 11.5–21.1ROR 15.6 · χ² 554 / p 8e-123 | 15.3 EB05 11.7 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=42 · ♀ 100% (drug 56%) | no trial data cached |
| Bladder transitional cell carcinoma | 10 | 12.8 6.8–23.7ROR 12.8 · χ² 96 / p 5e-23 | 10.7 EB05 5.4 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Nodal rhythm | 10 | 12.4 6.7–23.2ROR 12.5 · χ² 94 / p 2e-22 | 10.3 EB05 5.2 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Angle closure glaucoma | 17 | 12.1 7.5–19.5ROR 12.1 · χ² 162 / p 3e-37 | 11.0 EB05 6.7 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious n=17 | no trial data cached |
| Infusion site discharge | 11 | 11.8 6.5–21.3ROR 11.8 · χ² 97 / p 3e-23 | 9.8 EB05 5.2 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious n=9 | no trial data cached |
| Cardiac murmur | 55 | 11.5 8.9–15.0ROR 11.6 · χ² 516 / p 1e-114 | 11.2 EB05 8.8 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 11.1 · ♀ 95% (drug 56%) | no trial data cached |
| End stage renal disease | 116 | 11.5 9.6–13.8ROR 11.6 · χ² 1,096 / p 1e-240 | 11.3 EB05 9.6 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious PRR 10.4 | no trial data cached |
| Nocardiosis | 16 | 11.4 7.0–18.6ROR 11.4 · χ² 141 / p 9e-33 | 10.1 EB05 6.1 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious n=16 | no trial data cached |
| Systemic infection | 10 | 11.0 5.9–20.4ROR 11.0 · χ² 80 / p 1e-19 | 8.8 EB05 4.6 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Chronic kidney disease | 460 | 11.0 10.0–12.0ROR 11.4 · χ² 4,144 / p <1e-300 | 10.9 EB05 10.1 · IC025 +3.3 3/3 methods agree | Labeled (related wording) related wording | serious PRR 10.0 | no trial data cached |
| Aortic arteriosclerosis | 15 | 10.6 6.4–17.6ROR 10.6 · χ² 120 / p 2e-28 | 9.2 EB05 5.5 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious n=15 | no trial data cached |
| Amyloidosis | 10 | 10.6 5.7–19.7ROR 10.6 · χ² 77 / p 9e-19 | 8.4 EB05 4.4 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious n=10 | no trial data cached |
| Recalled product | 10 | 10.5 5.6–19.5ROR 10.5 · χ² 76 / p 1e-18 | 8.3 EB05 4.4 · IC025 +1.8 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=10 | no trial data cached |
| Hyponatraemia (low sodium) | 298 | 9.7 8.6–10.8ROR 9.9 · χ² 2,304 / p <1e-300 | 9.6 EB05 8.7 · IC025 +3.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 8.6 · 93% clinician | no trial data cached |
| Sacroiliitis | 10 | 9.6 5.2–17.9ROR 9.6 · χ² 69 / p 6e-17 | 7.5 EB05 4.1 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious n=9 | no trial data cached |
| Stress cardiomyopathy | 30 | 9.5 6.6–13.5ROR 9.5 · χ² 218 / p 2e-49 | 8.7 EB05 6.2 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious n=30 · ♀ 100% (drug 56%) · 100% clinician | no trial data cached |
| Infusion site bruising | 11 | 9.4 5.2–17.1ROR 9.4 · χ² 74 / p 3e-18 | 7.5 EB05 4.2 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious n=8 | no trial data cached |
| Blood potassium decreased | 155 | 9.4 8.0–11.0ROR 9.5 · χ² 1,151 / p 1e-252 | 9.2 EB05 8.0 · IC025 +2.9 3/3 methods agree | Labeled (related wording) related wording | serious PRR 7.8 | no trial data cached |
| Mean cell volume increased | 13 | 9.2 5.4–15.9ROR 9.2 · χ² 87 / p 5e-21 | 7.6 EB05 4.5 · IC025 +1.9 3/3 methods agree | Lab value / disease marker | serious n=9 | no trial data cached |
| Blood pressure diastolic abnormal | 13 | 9.2 5.4–15.9ROR 9.2 · χ² 87 / p 6e-21 | 7.6 EB05 4.5 · IC025 +1.9 3/3 methods agree | Lab value / disease marker | serious n=13 | 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 |
|---|---|---|---|---|---|---|
| Fatigue (tiredness) | 907 | 2.1 2.0–2.3ROR 2.2 · χ² 557 / p 2e-123 | 2.1 EB05 2.0 · IC025 +1.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 2.1 | no trial data cached |
| Nausea | 741 | 1.7 1.6–1.8ROR 1.8 · χ² 224 / p 5e-51 | 1.7 EB05 1.6 · IC025 +0.6 | Labeled adverse reaction exact term | serious PRR 2.0 | no trial data cached |
| Drug ineffective (drug did not work) | 735 | 1.0 0.9–1.1ROR 1.0 · χ² 0 / p 0.355 | 1.0 EB05 1.0 · IC025 -0.1 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | serious PRR 1.5 | no trial data cached |
| Diarrhoea (diarrhea) | 687 | 1.9 1.8–2.1ROR 2.0 · χ² 322 / p 3e-72 | 1.9 EB05 1.8 · IC025 +0.8 | Labeled adverse reaction exact term | serious PRR 1.9 | no trial data cached |
| Dizziness | 589 | 2.2 2.0–2.3ROR 2.2 · χ² 370 / p 1e-82 | 2.1 EB05 2.0 · IC025 +1.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.1 | no trial data cached |
| Pain | 562 | 1.7 1.5–1.8ROR 1.7 · χ² 151 / p 5e-35 | 1.7 EB05 1.5 · IC025 +0.6 | Labeled adverse reaction exact term | serious PRR 1.6 | no trial data cached |
| Off label use (used outside approved label) | 544 | 1.1 1.0–1.2ROR 1.1 · χ² 9 / p 0.001 | 1.1 EB05 1.1 · IC025 +0.0 | Reporting / coding artifact | serious PRR 1.3 | no trial data cached |
| Headache | 542 | 1.6 1.4–1.7ROR 1.6 · χ² 116 / p 3e-27 | 1.6 EB05 1.5 · IC025 +0.5 | Labeled adverse reaction exact term | serious PRR 1.8 | no trial data cached |
| Dyspnoea (shortness of breath) | 530 | 1.7 1.6–1.9ROR 1.7 · χ² 157 / p 2e-36 | 1.7 EB05 1.6 · IC025 +0.6 | Not in label — unassessed | serious PRR 1.6 | no trial data cached |
| Acute kidney injury (sudden kidney damage) | 472 | 5.6 5.2–6.2ROR 5.8 · χ² 1,806 / p <1e-300 | 5.6 EB05 5.2 · IC025 +2.3 3/3 methods agree | Labeled (related wording) related wording | serious PRR 5.1 | no trial data cached |
| Chronic kidney disease | 460 | 11.0 10.0–12.0ROR 11.4 · χ² 4,144 / p <1e-300 | 10.9 EB05 10.1 · IC025 +3.3 3/3 methods agree | Labeled (related wording) related wording | serious PRR 10.0 | no trial data cached |
| Arthralgia (joint pain) | 452 | 2.0 1.8–2.2ROR 2.0 · χ² 223 / p 9e-51 | 2.0 EB05 1.8 · IC025 +0.8 | Not in label — unassessed | serious PRR 2.1 | no trial data cached |
| Asthenia (weakness) | 440 | 2.1 1.9–2.3ROR 2.2 · χ² 266 / p 4e-60 | 2.1 EB05 2.0 · IC025 +0.9 | Not in label — unassessed | serious PRR 1.9 | no trial data cached |
| Hypertension (high blood pressure) | 401 | 3.4 3.1–3.8ROR 3.5 · χ² 697 / p 6e-154 | 3.4 EB05 3.2 · IC025 +1.6 3/3 methods agree | Likely indication confounding term in indications | serious PRR 3.1 | no trial data cached |
| Blood pressure increased | 399 | 4.7 4.3–5.2ROR 4.9 · χ² 1,179 / p 1e-258 | 4.7 EB05 4.3 · IC025 +2.1 3/3 methods agree | Lab value / disease marker | serious PRR 4.5 | 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.
- Chronic kidney disease-mineral and bone disorder — n=32, PRR 55.7
- Pneumonia viral — n=43, PRR 24.8
- Rebound acid hypersecretion — n=36, PRR 21.6
- Meningitis aseptic — n=43, PRR 17.6
- Breath sounds abnormal — n=42, PRR 15.6
- Cardiac murmur — n=55, PRR 11.5
- End stage renal disease — n=116, PRR 11.5
- Stress cardiomyopathy — n=30, PRR 9.5
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 Chlorthalidone?
In FDA FAERS, the most frequently co-reported reaction terms for Chlorthalidone are fatigue, nausea, diarrhoea, dizziness, pain, headache. 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 Chlorthalidone have an FDA boxed warning?
No. The FDA label retrieved for Chlorthalidone has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Chlorthalidone 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 01337f79-4b3d-4749-a82b-8d56c1aec179, effective 20220501; matched on
openfda.generic_name.exact:"CHLORTHALIDONE") - 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, 1,109 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.