Drug · FAERS side-effect profile with label screen
Dichlorphenamide side effects: what 1,639 FDA adverse event reports show
Drug class
FDA label (Established Pharmacologic Class) · compare the class
Who reports
1,639 reports · 28% serious · 13 with death outcome · 54% female
openFDA FAERS counts, all years, deduplication not applied
Used for
Dichlorphenamide tablets are indicated for the treatment of primary hyperkalemic periodic paralysis, primary hypokalemic periodic paralysis, and related variants. Dichlorphenamide tablets are an oral carbonic anhydrase inhibitor indicated for the treatment of primary hyperkalemic periodic paralysis, primary hypokalemic periodic paralysis, and related variants ( 1 )
FDA label, Indications and Usage
What it is
Dichlorphenamide tablets USP contain dichlorphenamide, an oral carbonic anhydrase inhibitor. Dichlorphenamide USP, a dichlorinated benzenedisulfonamide, is known chemically as 4, 5–dichloro- 1,3-benzenedisulfonamide.
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 10Labeled (related wording) 3Likely indication confounding 1Reporting / coding artifact 6Not in label — unassessed 20
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. 17 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 |
|---|---|---|---|---|---|---|
| Paralysis | 67 | 59.9 47.4–75.8ROR 62.4 · χ² 3,808 / p <1e-300 | 58.7 EB05 47.8 · IC025 +5.0 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 126.4 · 91% consumer | no trial data cached |
| Disease recurrence | 173 | 46.6 40.4–53.6ROR 51.9 · χ² 7,655 / p <1e-300 | 46.2 EB05 40.7 · IC025 +5.1 3/3 methods agree | Reporting / coding artifact | serious PRR 67.1 | no trial data cached |
| Blood potassium decreased | 94 | 40.1 32.9–48.8ROR 42.5 · χ² 3,538 / p <1e-300 | 39.7 EB05 33.4 · IC025 +4.7 3/3 methods agree | Labeled (related wording) related wording | serious PRR 52.0 | no trial data cached |
| Paraesthesia (tingling/numbness) | 303 | 24.6 22.2–27.3ROR 30.0 · χ² 6,883 / p <1e-300 | 24.5 EB05 22.3 · IC025 +4.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 19.8 | no trial data cached |
| Muscular weakness | 165 | 18.6 16.1–21.5ROR 20.6 · χ² 2,741 / p <1e-300 | 18.5 EB05 16.3 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious PRR 18.1 | no trial data cached |
| Taste disorder | 29 | 18.5 12.9–26.6ROR 18.9 · χ² 464 / p 4e-103 | 18.3 EB05 13.2 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious PRR 37.2 · 76% consumer | no trial data cached |
| Brain fog | 20 | 17.6 11.4–27.2ROR 17.8 · χ² 296 / p 1e-66 | 17.1 EB05 11.4 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 52.6 · ♀ 85% (drug 54%) · 90% consumer | no trial data cached |
| Dysgeusia (altered taste) | 94 | 16.1 13.2–19.6ROR 17.0 · χ² 1,321 / p 1e-289 | 16.0 EB05 13.5 · IC025 +3.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 18.9 | no trial data cached |
| Paraesthesia oral | 17 | 15.1 9.4–24.3ROR 15.3 · χ² 211 / p 5e-48 | 14.4 EB05 9.0 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 9.9 | no trial data cached |
| Aphasia (loss of speech) | 32 | 13.5 9.6–19.1ROR 13.8 · χ² 359 / p 2e-80 | 13.2 EB05 9.5 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 9.4 | no trial data cached |
| Hypokalaemia (low potassium) | 47 | 13.1 9.9–17.4ROR 13.5 · χ² 514 / p 3e-114 | 12.9 EB05 9.9 · IC025 +3.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 24.7 | no trial data cached |
| Muscle tightness | 15 | 11.9 7.2–19.7ROR 12.0 · χ² 139 / p 3e-32 | 10.6 EB05 6.3 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 28.5 | no trial data cached |
| Nephrolithiasis (kidney stones) | 42 | 11.8 8.7–15.8ROR 12.0 · χ² 403 / p 6e-90 | 11.4 EB05 8.6 · IC025 +2.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 25.6 | no trial data cached |
| Prescribed underdose | 18 | 11.6 7.3–18.3ROR 11.7 · χ² 163 / p 1e-37 | 10.5 EB05 6.6 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 9.1 | no trial data cached |
| Thirst | 16 | 11.5 7.1–18.7ROR 11.6 · χ² 143 / p 3e-33 | 10.3 EB05 6.2 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 11.0 | no trial data cached |
| Confusional state (confusion) | 126 | 10.0 8.4–11.8ROR 10.7 · χ² 1,014 / p 8e-223 | 9.8 EB05 8.4 · IC025 +3.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.7 | no trial data cached |
| Wrong technique in product usage process | 151 | 9.6 8.2–11.1ROR 10.4 · χ² 1,161 / p 1e-254 | 9.4 EB05 8.2 · IC025 +2.9 3/3 methods agree | Reporting / coding artifact | serious PRR 24.6 | no trial data cached |
| Muscle twitching | 17 | 9.4 5.9–15.1ROR 9.5 · χ² 120 / p 4e-28 | 8.2 EB05 5.2 · IC025 +2.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 16.1 | no trial data cached |
| Intentional dose omission | 19 | 8.9 5.7–13.9ROR 9.0 · χ² 125 / p 2e-29 | 7.8 EB05 5.1 · IC025 +2.1 3/3 methods agree | Reporting / coding artifact | serious PRR 6.0 | no trial data cached |
| Head discomfort | 12 | 8.7 5.0–15.3ROR 8.8 · χ² 74 / p 3e-18 | 7.1 EB05 4.1 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 8.0 | no trial data cached |
| Feeling abnormal | 160 | 8.5 7.3–9.9ROR 9.3 · χ² 1,065 / p 6e-234 | 8.4 EB05 7.3 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious PRR 9.1 | no trial data cached |
| Gastroenteritis viral | 12 | 8.5 4.8–14.9ROR 8.5 · χ² 72 / p 1e-17 | 6.9 EB05 4.0 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 8.4 | no trial data cached |
| Blood potassium increased | 10 | 7.9 4.3–14.6ROR 7.9 · χ² 53 / p 1e-13 | 6.2 EB05 3.5 · IC025 +1.5 3/3 methods agree | Labeled (related wording) related wording | serious PRR 14.9 | no trial data cached |
| Diplopia (double vision) | 15 | 7.4 4.5–12.2ROR 7.5 · χ² 77 / p 1e-18 | 6.2 EB05 3.9 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 9.8 | no trial data cached |
| Hypoaesthesia (numbness) | 81 | 6.9 5.6–8.6ROR 7.2 · χ² 407 / p 9e-91 | 6.7 EB05 5.5 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 6.6 | no trial data cached |
| Heart rate irregular | 12 | 6.8 3.8–11.9ROR 6.8 · χ² 53 / p 1e-13 | 5.5 EB05 3.3 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 9.2 | no trial data cached |
| Memory impairment | 72 | 6.7 5.3–8.4ROR 7.0 · χ² 346 / p 2e-77 | 6.5 EB05 5.3 · IC025 +2.3 3/3 methods agree | Labeled (related wording) related wording | serious PRR 7.7 | no trial data cached |
| Hypersomnia | 14 | 6.3 3.7–10.5ROR 6.3 · χ² 57 / p 2e-14 | 5.3 EB05 3.3 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 6.8 | no trial data cached |
| Limb discomfort | 15 | 6.2 3.7–10.3ROR 6.3 · χ² 60 / p 4e-15 | 5.3 EB05 3.4 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 7.3 | no trial data cached |
| Intentional product use issue | 42 | 6.1 4.5–8.2ROR 6.2 · χ² 175 / p 3e-40 | 5.8 EB05 4.4 · IC025 +2.0 3/3 methods agree | Reporting / coding artifact | serious PRR 4.0 | no trial data cached |
| Disturbance in attention | 25 | 5.9 4.0–8.7ROR 6.0 · χ² 97 / p 3e-23 | 5.4 EB05 3.8 · IC025 +1.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.9 | no trial data cached |
| Tinnitus (ringing in the ears) | 21 | 5.8 3.8–8.9ROR 5.9 · χ² 80 / p 2e-19 | 5.2 EB05 3.6 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 5.3 | no trial data cached |
| Depressed mood | 24 | 5.8 3.9–8.7ROR 5.9 · χ² 92 / p 5e-22 | 5.3 EB05 3.7 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 3.9 | no trial data cached |
| Mental impairment | 11 | 5.8 3.2–10.5ROR 5.8 · χ² 39 / p 2e-10 | 4.8 EB05 2.8 · IC025 +1.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.1 | no trial data cached |
| Cognitive disorder | 21 | 5.8 3.8–8.8ROR 5.8 · χ² 78 / p 4e-19 | 5.2 EB05 3.6 · IC025 +1.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.0 | no trial data cached |
| Burning sensation | 31 | 5.7 4.0–8.0ROR 5.7 · χ² 115 / p 5e-27 | 5.2 EB05 3.9 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 13.3 | no trial data cached |
| Muscle spasms | 77 | 5.4 4.3–6.7ROR 5.6 · χ² 272 / p 2e-61 | 5.2 EB05 4.3 · IC025 +2.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 9.5 | no trial data cached |
| Migraine | 39 | 5.3 3.9–7.2ROR 5.4 · χ² 131 / p 1e-30 | 5.0 EB05 3.8 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 6.0 · ♀ 79% (drug 54%) | no trial data cached |
| Product dose omission | 24 | 4.6 3.1–6.9ROR 4.7 · χ² 65 / p 4e-16 | 4.3 EB05 3.0 · IC025 +1.4 3/3 methods agree | Reporting / coding artifact | serious PRR 13.1 | no trial data cached |
| Intentional product misuse | 29 | 4.3 3.0–6.1ROR 4.3 · χ² 70 / p 3e-17 | 4.0 EB05 2.9 · IC025 +1.4 3/3 methods agree | Reporting / coding artifact | serious PRR 3.5 | 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 |
|---|---|---|---|---|---|---|
| Paraesthesia (tingling/numbness) | 303 | 24.6 22.2–27.3ROR 30.0 · χ² 6,883 / p <1e-300 | 24.5 EB05 22.3 · IC025 +4.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 19.8 | no trial data cached |
| Disease recurrence | 173 | 46.6 40.4–53.6ROR 51.9 · χ² 7,655 / p <1e-300 | 46.2 EB05 40.7 · IC025 +5.1 3/3 methods agree | Reporting / coding artifact | serious PRR 67.1 | no trial data cached |
| Muscular weakness | 165 | 18.6 16.1–21.5ROR 20.6 · χ² 2,741 / p <1e-300 | 18.5 EB05 16.3 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious PRR 18.1 | no trial data cached |
| Feeling abnormal | 160 | 8.5 7.3–9.9ROR 9.3 · χ² 1,065 / p 6e-234 | 8.4 EB05 7.3 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious PRR 9.1 | no trial data cached |
| Wrong technique in product usage process | 151 | 9.6 8.2–11.1ROR 10.4 · χ² 1,161 / p 1e-254 | 9.4 EB05 8.2 · IC025 +2.9 3/3 methods agree | Reporting / coding artifact | serious PRR 24.6 | no trial data cached |
| Confusional state (confusion) | 126 | 10.0 8.4–11.8ROR 10.7 · χ² 1,014 / p 8e-223 | 9.8 EB05 8.4 · IC025 +3.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.7 | no trial data cached |
| Dysgeusia (altered taste) | 94 | 16.1 13.2–19.6ROR 17.0 · χ² 1,321 / p 1e-289 | 16.0 EB05 13.5 · IC025 +3.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 18.9 | no trial data cached |
| Blood potassium decreased | 94 | 40.1 32.9–48.8ROR 42.5 · χ² 3,538 / p <1e-300 | 39.7 EB05 33.4 · IC025 +4.7 3/3 methods agree | Labeled (related wording) related wording | serious PRR 52.0 | no trial data cached |
| Hypoaesthesia (numbness) | 81 | 6.9 5.6–8.6ROR 7.2 · χ² 407 / p 9e-91 | 6.7 EB05 5.5 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 6.6 | no trial data cached |
| Muscle spasms | 77 | 5.4 4.3–6.7ROR 5.6 · χ² 272 / p 2e-61 | 5.2 EB05 4.3 · IC025 +2.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 9.5 | no trial data cached |
| Memory impairment | 72 | 6.7 5.3–8.4ROR 7.0 · χ² 346 / p 2e-77 | 6.5 EB05 5.3 · IC025 +2.3 3/3 methods agree | Labeled (related wording) related wording | serious PRR 7.7 | no trial data cached |
| Paralysis | 67 | 59.9 47.4–75.8ROR 62.4 · χ² 3,808 / p <1e-300 | 58.7 EB05 47.8 · IC025 +5.0 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 126.4 · 91% consumer | no trial data cached |
| Hypokalaemia (low potassium) | 47 | 13.1 9.9–17.4ROR 13.5 · χ² 514 / p 3e-114 | 12.9 EB05 9.9 · IC025 +3.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 24.7 | no trial data cached |
| Intentional product use issue | 42 | 6.1 4.5–8.2ROR 6.2 · χ² 175 / p 3e-40 | 5.8 EB05 4.4 · IC025 +2.0 3/3 methods agree | Reporting / coding artifact | serious PRR 4.0 | no trial data cached |
| Nephrolithiasis (kidney stones) | 42 | 11.8 8.7–15.8ROR 12.0 · χ² 403 / p 6e-90 | 11.4 EB05 8.6 · IC025 +2.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 25.6 | 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.
- Muscular weakness — n=165, PRR 18.6
- Taste disorder — n=29, PRR 18.5
- Brain fog — n=20, PRR 17.6
- Aphasia — n=32, PRR 13.5
- Feeling abnormal — n=160, PRR 8.5
- Hypoaesthesia — n=81, PRR 6.9
- Tinnitus — n=21, PRR 5.8
- Depressed mood — n=24, PRR 5.8
- Burning sensation — n=31, PRR 5.7
- Migraine — n=39, PRR 5.3
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 Dichlorphenamide?
In FDA FAERS, the most frequently co-reported reaction terms for Dichlorphenamide are paraesthesia, muscular weakness, feeling abnormal, confusional state, dysgeusia, blood potassium decreased. 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 Dichlorphenamide have an FDA boxed warning?
No. The FDA label retrieved for Dichlorphenamide has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Dichlorphenamide 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 64bf0c71-2113-47dc-8ce5-7fe535e558dc, effective 20260305; matched on
openfda.generic_name.exact:"DICHLORPHENAMIDE") - 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, 57 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.