Prescription medicine
Tiopronin Brand names: Thiola, Venxxiva
Tiopronin (Thiola) is a prescription medicine with an FDA approval on record since 1988. FDA's NDC Directory lists it from 6 generic labelers.
- Generic listed
Check it at the source: the tiopronin FDA label on DailyMed (effective October 7, 2025, Mission Pharmacal Company); the NDA 19569 record on Drugs@FDA; every tiopronin label on DailyMed.
Highlights of the record
FDA label of October 7, 2025; NDC Directory, Drugs@FDA and Orange Book, October 8, 2026
Used for
From the label: indications and usageTHIOLA EC is indicated, in combination with high fluid intake, alkali, and diet modification, for the prevention of cystine stone formation in adults and pediatric patients 20 kg and greater with severe homozygous cystinuria, who are not responsive to these measures alone.
Forms and strengths
- 100 mg
- 300 mg
Delayed-release tablet; sugar-coated tablet.
On the market
- Earliest approval on file
- August 11, 1988 Thiola, Mission Pharma; Drugs@FDA’s file, where older or withdrawn approvals can be missing
- Generic approvals
- 6 first April 26, 2021; 4 with a marketed status in Drugs@FDA
- Labelers listed (NDC)
- 8 of which 6 under generic applications, 1 under brand applications, repackagers included
- Last listed patent
- November 14, 2038 Thiola Ec tablets; not a generic launch date
Supply and safety
- Pharmacy cost (NADAC)
- Not in the survey
- Shortage (FDA)
- No current entry
- Recalls by its makers (FDA)
- No recall recorded
- FAERS reports
- 2,449 through July 30, 2026
What is tiopronin used for?
From the label: indications and usageTHIOLA EC is indicated, in combination with high fluid intake, alkali, and diet modification, for the prevention of cystine stone formation in adults and pediatric patients 20 kg and greater with severe homozygous cystinuria, who are not responsive to these measures alone. THIOLA EC is a reducing and complexing thiol indicated, in combination with high fluid intake, alkali, and diet modification, for the prevention of cystine stone formation in adults and pediatric patients 20 kg and greater with severe homozygous cystinuria, who are not responsive to these measures alone.
FDA pharmacologic class: Reducing and Complexing Thiol.
Source: FDA drug label (Thiola EC), Mission Pharmacal Company, effective October 7, 2025 (SPL set 20298a52-a194-a161-8632-d84b6f26e23c), via openFDA; the full label on DailyMed
Is there a generic for tiopronin (Thiola)?
The FDA approved the first generic tiopronin on April 26, 2021. 6 generic applications are approved; 4 of them carry a current (not discontinued) marketing status in Drugs@FDA; that status is not evidence that the generic is on sale.
FDA's NDC Directory lists tiopronin from 6 labelers under a generic (ANDA) application and from 1 brand labeler. A listing means the company has registered the product for sale; it does not show that every pharmacy stocks it.
The Orange Book lists 1 patent for Thiola Ec tablets, the last expiring on November 14, 2038. A patent or exclusivity date is not the date a generic goes on sale: court cases and settlements move it either way.
- 1988 earliest approval on file
- 2021 first generic approved
- 2038 last listed patent
Source: Drugs@FDA, FDA NDC Directory and the Orange Book (openFDA bulk files, October 8, 2026)
What do FAERS reports show for tiopronin?
The FDA Adverse Event Reporting System holds 2,449 reports that list tiopronin among the medicines taken, through July 30, 2026, each a report of something that happened, not proof the medicine caused it; 88 are coded as a death and 308 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is.
Reports received each year
The most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026
What next?
- Tiopronin side effects
- the label's list beside FAERS reports
- Check an interaction
- what two or more labels say about each other