Tiopronin side effects: what 2,449 FDA adverse event reports show

Tiopronin · Venxxiva · 23 reaction terms · 1,557 drug–reaction co-reports · data 2026-09-14

Drug class

Reducing and Complexing Thiol

FDA label (Established Pharmacologic Class)

Brand names

Venxxiva

openFDA label

Who reports

2,449 reports · 20% serious · 88 with death outcome · 51% female

openFDA FAERS counts, all years, deduplication not applied

Used for

VENXXIVA is indicated, in combination with high fluid intake, alkali, and diet modification, for the prevention of cystine stone formation in adults and pediatric patients 9 years of age and older with severe homozygous cystinuria, who are not responsive to these measures alone. Additional pediatric use information is approved for Mission Pharmacal Company’s Thiola EC (tiopronin delayed-release) tablets.

FDA label, Indications and Usage

What it is

VENXXIVA (tiopronin) delayed-release tablets are a reducing and cystine-binding thiol drug (CBTD) for oral use. Tiopronin is N‑(2‑Mercaptopropionyl) glycine and has the following structure: Tiopronin has the empirical formula C 5 H 9 NO 3 S and a molecular weight of 163.19.

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 17 strongest signals

Labeled adverse reaction 7Labeled (related wording) 2Reporting / coding artifact 2Lab value / disease marker 1Not in label — unassessed 5

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.
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. 6 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
Flank pain	38	34.9 25.4–47.9ROR 35.4 · χ² 1,213 / p 4e-266	34.2 EB05 26.0 · IC025 +4.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 24.8 · 92% consumer	no trial data cached
Renal pain	40	32.5 23.9–44.3ROR 33.1 · χ² 1,187 / p 2e-260	32.0 EB05 24.5 · IC025 +4.0 3/3 methods agree	Labeled (related wording) related wording	serious PRR 14.1 · 98% consumer	no trial data cached
Proteinuria	42	19.1 14.2–25.8ROR 19.4 · χ² 702 / p 6e-155	18.9 EB05 14.5 · IC025 +3.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 3.0 · 88% consumer	no trial data cached
Nephrolithiasis (kidney stones)	92	17.3 14.1–21.1ROR 17.9 · χ² 1,393 / p <1e-300	17.2 EB05 14.4 · IC025 +3.6 3/3 methods agree	Not in label — unassessed	serious PRR 9.7 · 88% consumer	no trial data cached
Rash generalised	42	13.7 10.2–18.5ROR 13.9 · χ² 482 / p 4e-107	13.4 EB05 10.2 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	100% consumer	no trial data cached
Drug dose omission	257	13.1 11.7–14.8ROR 14.6 · χ² 2,890 / p <1e-300	13.1 EB05 11.8 · IC025 +3.5 3/3 methods agree	Reporting / coding artifact	serious PRR 3.9 · 98% consumer	no trial data cached
Ageusia (loss of taste)	28	9.6 6.6–13.9ROR 9.7 · χ² 207 / p 3e-47	8.8 EB05 6.2 · IC025 +2.4 3/3 methods agree	Labeled adverse reaction exact term	85% consumer	no trial data cached
Mouth ulceration	16	6.5 4.0–10.6ROR 6.6 · χ² 69 / p 4e-17	5.6 EB05 3.6 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 3.2	no trial data cached
Blood urine present	14	6.3 3.7–10.6ROR 6.3 · χ² 57 / p 2e-14	5.3 EB05 3.4 · IC025 +1.5 3/3 methods agree	Lab value / disease marker	serious PRR 3.8	no trial data cached
Kidney infection	13	5.7 3.3–9.8ROR 5.7 · χ² 46 / p 7e-12	4.8 EB05 3.0 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 7.2	no trial data cached
Lymphadenopathy	23	5.6 3.7–8.4ROR 5.6 · χ² 82 / p 8e-20	5.0 EB05 3.5 · IC025 +1.6 3/3 methods agree	Labeled adverse reaction exact term	96% consumer	no trial data cached
Tubulointerstitial nephritis	12	5.5 3.1–9.7ROR 5.5 · χ² 40 / p 1e-10	4.6 EB05 2.8 · IC025 +1.2 3/3 methods agree	Not in label — unassessed	serious PRR 16.2	no trial data cached
Drug ineffective (drug did not work)	769	5.0 4.7–5.3ROR 6.8 · χ² 2,622 / p <1e-300	5.0 EB05 4.7 · IC025 +2.2 3/3 methods agree	Reporting / coding artifact	serious PRR 5.6 · 95% consumer	no trial data cached
Dyspepsia (indigestion)	57	5.0 3.9–6.4ROR 5.1 · χ² 178 / p 7e-41	4.8 EB05 3.8 · IC025 +1.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 1.0 · 98% consumer	no trial data cached
Dysgeusia (altered taste)	43	4.9 3.7–6.6ROR 5.0 · χ² 131 / p 1e-30	4.7 EB05 3.6 · IC025 +1.7 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 2.8 · 93% consumer	no trial data cached
Taste disorder	11	4.7 2.6–8.5ROR 4.7 · χ² 28 / p 5e-8	4.0 EB05 2.4 · IC025 +1.0 3/3 methods agree	Labeled (related wording) related wording	–	no trial data cached
Rash pruritic	26	4.1 2.8–6.1ROR 4.2 · χ² 59 / p 9e-15	3.9 EB05 2.8 · IC025 +1.3 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 1.0 · 96% consumer	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
Drug ineffective (drug did not work)	769	5.0 4.7–5.3ROR 6.8 · χ² 2,622 / p <1e-300	5.0 EB05 4.7 · IC025 +2.2 3/3 methods agree	Reporting / coding artifact	serious PRR 5.6 · 95% consumer	no trial data cached
Drug dose omission	257	13.1 11.7–14.8ROR 14.6 · χ² 2,890 / p <1e-300	13.1 EB05 11.8 · IC025 +3.5 3/3 methods agree	Reporting / coding artifact	serious PRR 3.9 · 98% consumer	no trial data cached
Nephrolithiasis (kidney stones)	92	17.3 14.1–21.1ROR 17.9 · χ² 1,393 / p <1e-300	17.2 EB05 14.4 · IC025 +3.6 3/3 methods agree	Not in label — unassessed	serious PRR 9.7 · 88% consumer	no trial data cached
Dyspepsia (indigestion)	57	5.0 3.9–6.4ROR 5.1 · χ² 178 / p 7e-41	4.8 EB05 3.8 · IC025 +1.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 1.0 · 98% consumer	no trial data cached
Dysgeusia (altered taste)	43	4.9 3.7–6.6ROR 5.0 · χ² 131 / p 1e-30	4.7 EB05 3.6 · IC025 +1.7 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 2.8 · 93% consumer	no trial data cached
Rash generalised	42	13.7 10.2–18.5ROR 13.9 · χ² 482 / p 4e-107	13.4 EB05 10.2 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	100% consumer	no trial data cached
Proteinuria	42	19.1 14.2–25.8ROR 19.4 · χ² 702 / p 6e-155	18.9 EB05 14.5 · IC025 +3.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 3.0 · 88% consumer	no trial data cached
Renal pain	40	32.5 23.9–44.3ROR 33.1 · χ² 1,187 / p 2e-260	32.0 EB05 24.5 · IC025 +4.0 3/3 methods agree	Labeled (related wording) related wording	serious PRR 14.1 · 98% consumer	no trial data cached
Flank pain	38	34.9 25.4–47.9ROR 35.4 · χ² 1,213 / p 4e-266	34.2 EB05 26.0 · IC025 +4.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 24.8 · 92% consumer	no trial data cached
Ageusia (loss of taste)	28	9.6 6.6–13.9ROR 9.7 · χ² 207 / p 3e-47	8.8 EB05 6.2 · IC025 +2.4 3/3 methods agree	Labeled adverse reaction exact term	85% consumer	no trial data cached
Rash pruritic	26	4.1 2.8–6.1ROR 4.2 · χ² 59 / p 9e-15	3.9 EB05 2.8 · IC025 +1.3 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 1.0 · 96% consumer	no trial data cached
Lymphadenopathy	23	5.6 3.7–8.4ROR 5.6 · χ² 82 / p 8e-20	5.0 EB05 3.5 · IC025 +1.6 3/3 methods agree	Labeled adverse reaction exact term	96% consumer	no trial data cached
Mouth ulceration	16	6.5 4.0–10.6ROR 6.6 · χ² 69 / p 4e-17	5.6 EB05 3.6 · IC025 +1.6 3/3 methods agree	Not in label — unassessed	serious PRR 3.2	no trial data cached
Blood urine present	14	6.3 3.7–10.6ROR 6.3 · χ² 57 / p 2e-14	5.3 EB05 3.4 · IC025 +1.5 3/3 methods agree	Lab value / disease marker	serious PRR 3.8	no trial data cached
Kidney infection	13	5.7 3.3–9.8ROR 5.7 · χ² 46 / p 7e-12	4.8 EB05 3.0 · IC025 +1.3 3/3 methods agree	Not in label — unassessed	serious PRR 7.2	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.

Nephrolithiasis — n=92, PRR 17.3
Rash generalised — n=42, PRR 13.7

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 Tiopronin?

In FDA FAERS, the most frequently co-reported reaction terms for Tiopronin are nephrolithiasis, dyspepsia, dysgeusia, rash generalised, proteinuria, renal pain. 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 Tiopronin have an FDA boxed warning?

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

Do FAERS signals prove that Tiopronin 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 02e24443-04c6-4b98-a395-49aec4a468de, effective 20251222; matched on openfda.generic_name.exact:"TIOPRONIN")
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, 23 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.