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TIOPRONIN 100 mg Tablet, Delayed Release, 300-count — NDC 00254-3034-30 package photo

TIOPRONIN 100 mg Tablet, Delayed Release, 300-count

by Par Health USA, LLC · 300 TABLET, DELAYED RELEASE in 1 BOTTLE (0254-3034-30)
NDC 00254-3034-30
🏷️ FDA NDC (as labeled) 0254-3034-30 billing pads the labeler segment with a zero
Rx only Generic On market Non-controlled
🗂️ Data synced Sep 17, 2026 · sources: openFDA · FDA label (DailyMed) · FDA Orange & Purple Book · First Databank · CMS NADAC, ASP, Medicare & Medicaid · RxNorm
📋 All sources & update times →

This page is curated, coded, and maintained by

Compiled from public FDA, CMS, DailyMed, NADAC, and related drug data sources. Editorial policy

🆔 Identity & classification

FDA NDC (as labeled) 0254-3034-30
Product NDC 0254-3034
11-digit billing NDC 00254303430
NCPDP billing unit EA — each (per item)
UNII C5W04GO61S
UPC 2307744035090, 0302543034307
Application # ANDA217219
SPL Set ID 5396b9fd-5385-44fd-a8ba-e56a46a33bc7
Established class (EPC) Reducing and Complexing Thiol
Mechanism of action Cystine Disulfide Reduction
Chemical class N-substituted Glycines
DEA schedule Non-controlled
Marketing category ANDA
Marketing status On market
FDA listing status Listed (active directory)
Marketing start 2024-06-26
Route ORAL
Dosage form TABLET, DELAYED RELEASE
Substance TIOPRONIN
GCN Seq No 079977
GCN 46629
HICL code 003714
Ingredient (HICL) Tiopronin
HIC1 code R
Therapeutic class — broad (HIC1) Kidney/Urinary Tract
HIC2 code R4
Therapeutic class — intermediate (HIC2) Agents Affecting Renal Calculi
HIC3 code R4A
Therapeutic class — specific (HIC3) Kidney Stone Agents
AHFS code 92:92.00.00
AHFS class Other Miscellaneous Therapeutic Agents
FDB label name TIOPRONIN DR 100 MG TABLET
FDB brand name Tiopronin
Legend status F — Federal legend — prescription drug or device
TE code (Orange Book) AB · RLD · RS
Why two NDCs? The FDA registers this code as 0254-3034-30 — a 4-4-2 layout, and that's what's printed on the package and shown on DailyMed. For insurance claims, every NDC is standardized to a uniform 11-digit 5-4-2 format by adding a zero to the labeler segment → 00254-3034-30. Same drug, same package — only the format differs.
Where does this data come from?
Identifiers from the FDA openFDA NDC Directory and Structured Product Labeling; RxCUI from RxNorm (NLM); GPI from Medi-Span; GCN / HIC / AHFS / legend from First Databank.

🏭 Manufacturer & labeler

LabelerPar Health USA, LLC
Application holderPH HEALTH LTD
FDA applicationANDA217219 (ANDA)
Labeler code00254
First marketedJun 2024
Product typeHuman Prescription Drug
Portfolio212 products on file
The labeler markets the product; the application holder owns the FDA approval. They’re often the same company but can differ (e.g. a repackager or an authorized generic). A mailing address / phone appears here when the manufacturer includes it in the product’s FDA label (not all do).
Where does this data come from?
Labeler, application holder and registered establishment from the FDA openFDA NDC Directory and Drugs@FDA; address/contact from the product’s FDA label.

🩺 Clinical

Label name TIOPRONIN DR 100 MG TABLET Ingredient Tiopronin
📗 Our plain-language guide HelloPharmacist
  • Tiopronin is used to prevent kidney stones made of cystine — a substance that builds up in people with a rare inherited condition called cystinuria. If your body produces too much...
  • It depends on which product you have. Thiola tablets and Tiopronin regular tablets should be taken at least 1 hour before or 2 hours after meals. Thiola EC and Tiopronin delayed-re...
  • How should I take my tiopronin — with or without food?
  • The most common ones are nausea, loose stools, mouth sores, rash, fatigue, fever, and joint pain. A reduced sense of taste can also happen, but it often gets better on its own. The...
📖 Read our full Tiopronin guide →
Where does this data come from?
Plain-language summary from MedlinePlus (U.S. National Library of Medicine); supplement & herbal interactions and nutrient depletion data from the Natural Medicines database; our full guide is HelloPharmacist editorial content.

💊 What it looks like

Color white
ShapeRound
ImprintD3
Size11 mm
ScoringNot scored
One label can cover several strengths, so colors may be combined — always confirm a loose pill against the dispensed prescription label or a pharmacist.
Where does this data come from?
Physical description (imprint, shape, color, scoring, coating) from this product’s FDA Structured Product Labeling (SPL), mirrored from DailyMed / openFDA.

🧪 Inactive Ingredients / Excipients

Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.

💡 Tap an ingredient (hover on desktop) to see what it is and why it’s used.

  • UNII 5138Q19F1X
    Ammonia is a colorless gas made from nitrogen and hydrogen. It's used in medicines as a pH buffer to maintain the correct acidity level and help keep the product stable.
  • UNII 3SY5LH9PMK
    Anhydrous lactose is a milk sugar with no water content. It acts as a filler and binder in tablets and capsules, adding bulk and helping ingredients stick together.
  • UNII 92RU3N3Y1O
    Dimethicone is a silicone-based oil that acts as an anti-foaming agent and lubricant in medicines. It reduces gas bubbles in liquid formulations and helps coat and protect the stomach lining when ingested.
  • UNII 1K09F3G675
    Ferric oxide red is an inorganic iron compound used as a colorant in medicines. It gives tablets, capsules, or other dosage forms a red or reddish tint for identification and appearance.
  • UNII 9XZ8H6N6OH
    A plant-based cellulose derivative used as a binder to hold tablet ingredients together, a thickener in liquids, and a coating agent to control how fast the medicine dissolves.
  • UNII 3NXW29V3WO
    Hypromellose is a plant-based thickener made from cellulose. It's used in medicines as a binder to hold ingredients together, a coating for tablets, and a thickener for liquids.
  • UNII 7773C1ROEU
    Low-substituted hydroxypropyl cellulose is a plant-derived thickener and binder made from cellulose. In medicines, it helps bind tablet ingredients together, controls how quickly the medicine dissolves, and improves texture in liquids and semi-solid formulations.
  • UNII 70097M6I30
    Magnesium stearate is a salt made from magnesium and stearic acid, a fatty substance. It's used in tablets and capsules as a lubricant and glidant to help ingredients flow smoothly during manufacturing and prevent sticking.
  • UNII NX76LV5T8J
    A synthetic plastic polymer made from methacrylic acid and ethyl acrylate. It's used as a coating or binder to control how and where the medicine dissolves in your digestive system.
  • UNII 6DC9Q167V3
    Propylene glycol is a clear liquid derived from petroleum or vegetable sources. It acts as a solvent, humectant, and preservative in medicines, helping dissolve active ingredients and maintain product stability.
  • UNII 46N107B71O
    Shellac is a natural resin secreted by the lac beetle. It's used as a coating on tablets and capsules to control how quickly the medicine dissolves and to improve appearance and stability.
  • UNII ETJ7Z6XBU4
    Silicon dioxide is a naturally occurring mineral used as a glidant and anti-caking agent. It helps powder ingredients flow smoothly and prevents clumping during manufacturing and storage.
  • UNII 7SEV7J4R1U
    A powder made from a naturally occurring mineral. In medicines, talc works as a glidant and anti-caking agent, helping tablets and capsules flow smoothly during manufacturing and preventing clumping.
  • UNII 8Z96QXD6UM
    Triethyl citrate is a clear liquid derived from citric acid. It acts as a plasticizer and solvent in tablet coatings and film formulations, helping the coating remain flexible and adhere properly to the medicine.

14 inactive ingredients listed in the exact product block matched to this NDC.

Where does this data come from?
Data sourced from official FDA Structured Product Labeling (SPL) via DailyMed — ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.

Inactive ingredient FAQ

Are inactive ingredients the same for every manufacturer?
No. Inactive ingredients can differ by manufacturer, dosage form, strength, and package / product version.
Why might an inactive ingredient be missing?
Some SPLs do not provide a complete structured inactive-ingredient list, and older or unusual labels may only include the information in narrative text.
Can inactive ingredients matter?
Yes. They can matter for allergies, intolerances, dyes, gluten / lactose concerns, preservatives, and formulation differences — but confirm with a pharmacist or the manufacturer when it’s clinically important.

💲 Pricing

A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.

Price systemPer eachPer package
Retail pharmacies payNADAC · weekly Not in the retail survey — common for institutional, discontinued, or low-volume packs.
Medicaid paysCMS SDUD · 12 mo No recent Medicaid claims on file for this NDC — rare and low-volume NDCs are suppressed in the public data.
Medicare drug plans payPart D · Q2 2026 $20.80 $6,239.31 / 300 tablets
Where does this data come from?
NADAC (National Average Drug Acquisition Cost) is the CMS weekly pharmacy-acquisition-cost survey — what pharmacies pay. ASP (Average Sales Price) is the CMS Medicare Part B drug-payment file, published quarterly. Medicaid pays is computed by us from CMS State Drug Utilization Data (total reimbursed ÷ units, trailing 12 months) — gross of rebates and inclusive of dispensing fees, so it reflects what Medicaid paid, not an acquisition cost. Medicare drug plans pay is the median negotiated point-of-sale unit cost across plans listing this NDC in the CMS quarterly Prescription Drug Plan pricing files, before rebates. The VA pays is the federal contract price (FSS, and the statutory Big 4 ceiling where listed) from the VA National Acquisition Center pharmaceutical price file. All are free public government data; each measures a different payer, so the figures are not directly comparable.

🔁 Therapeutic equivalents

ProductLabelerPackNADAC/unitTEStatusPrice vs. this
Thiola EC 100 mg 00178-0902-01 Mission 300 tablets — AB FDA listed —
Tiopronin 100 mgthis 00254-3034-30 Par 300 tablets — AB FDA listed —
Tiopronin 100 mg 00480-9227-55 Teva 300 tablets — AB FDA listed —
Tiopronin 100 mg 13668-0691-03 Torrent 300 tablets — AB FDA listed —
Tiopronin 100 mg 44523-0054-01 BioComp 300 tablets — AB FDA listed —
Venxxiva 100 mg 70709-0121-30 Cycle 300 tablets — AB FDA listed —
About this product: this is a generic version of the medicine. FDA equivalence ratings are shown when available, and other versions are listed above, least expensive first.
Where does this data come from?
Equivalents are other NDCs of the same ingredient, form and route from the openFDA NDC Directory, ranked least-expensive-first by NADAC. Therapeutic-equivalence (AB) ratings come from the FDA Orange Book; biologics use the FDA Purple Book for biosimilar & interchangeable status.

⏳ Availability & generic status

🏛️
2024
On the market since
Jun 2024
📍
2026
Currently FDA-listed
2 years listed
🔓
·
Generic on the market
this product is a generic
✅This is a generic drug

This product is an FDA-approved generic. Other versions of the same drug are listed under Therapeutic equivalents, least expensive first.

Where does this data come from?
Patents and exclusivity from the FDA Orange Book (small-molecule drugs), refreshed from public FDA data. Generic launch timing is an estimate, not a guarantee.

📊 Medicare Part D spend CMS · PART D · 2026 (Q1)

Medicare Part D (outpatient prescription) spending for Tiopronin — the program that covers self-administered drugs. 3 manufacturers.
⚠️ Drug-level data: CMS publishes Part D spending by drug, not by NDC — these figures combine every manufacturer, strength and package size sold under the name Tiopronin. That’s a different level of aggregation than the Medicaid card above, which is specific to this exact 11-digit NDC (pack size included), so the two aren’t directly comparable.
Period
Total Part D spend
$441.5K
Claims incl. refills
99
Beneficiaries
42
Spend / beneficiary
$10,511.18
Spend / claim
$4,459.29
Trend by period
💵 About the dollar figures: spending is what Part D plans paid before confidential manufacturer rebates, so the program’s real net cost is lower. A blank patient count means fewer than 11 people — CMS hides counts that small to protect privacy. Source: CMS Medicare Quarterly Part D Spending by Drug (data.cms.gov), updated quarterly.

📦 Packaging — all sizes for this product

Package NDCDescription Marketing startStatus
00254-3034-30 You're viewing this 300 TABLET, DELAYED RELEASE in 1 BOTTLE (0254-3034-30) 2024-06-26 Active

🧭 About this NDC listing & data coverage

Finished prescription product
What data is (and isn’t) available for this NDC — tap to expand
NDC identity (package / product / labeler codes) ✓ Available
Labeler ✓ Available
Product & package description ✓ Available
Marketing category & status ✓ Available
Active ingredient / dosage form / route ✓ Available
FDA label (SPL via DailyMed) ✓ Available
Package photos ✓ Available
Inactive ingredients (structured) ✓ Available
NADAC pharmacy acquisition price (CMS) — Not published for this NDC CMS publishes NADAC only for NDCs reported in its retail-pharmacy survey.
Orange Book / therapeutic-equivalence data ✓ Available
HCPCS J-code billing crosswalk — Not published for this NDC Most self-administered / retail products have no J-code — that is normal.
Medicaid utilization (CMS SDUD) — Not published for this NDC CMS reports utilization only for NDCs with Medicaid claims above its privacy threshold.
“Not published” reflects what the public FDA / CMS / NLM sources provide for this exact package code — it is a property of the data feeds, not a judgment about the product.

Questions about this listing

Why is there no price listed?
The pricing shown on our NDC pages comes from CMS NADAC, a voluntary survey of retail community pharmacy invoices. CMS does not publish a NADAC for every NDC — packages outside the retail survey (institutional and hospital products, bulk packages, discontinued items, and many OTC items) may never receive one. A missing price reflects the survey's scope, not this product's actual cost, and does not mean the product is free or unavailable.
Is the NDC printed on the package the same as the 11-digit billing NDC?
Yes, they identify this exact package in different formats. The FDA registers it as 0254-3034-30, which is what is printed on the packaging and shown on DailyMed. Insurance claims use a fixed 11-digit 5-4-2 format, so the short segment is padded with a leading zero: 00254-3034-30, written without dashes as 00254303430. The Identity section at the top of this page lists every form of this code.
What do the three segments of this NDC mean?
In 00254-3034-30, the first segment (00254) is the labeler code FDA assigned to Par Health USA, LLC; the middle segment (3034) identifies this specific product — its ingredient, strength, and dosage form; and the last segment (30) identifies this exact package size and type. Together they name one specific package of one specific product.
Is this package still being marketed?
Yes, per the latest FDA NDC Directory data on this page: this package is listed as actively marketed, with no marketing end date reported by Par Health USA, LLC. Listing status can change — the directory data on this page refreshes weekly.
Who lists this product with the FDA?
Par Health USA, LLC is the labeler of record for this NDC — the company under whose FDA-assigned code the package is listed. The labeler may be the manufacturer itself or a distributor marketing the product under its own code.
Do I need a prescription for this product?
This NDC is listed with FDA as a prescription product, so it is dispensed under a prescriber's order. Your pharmacist can tell you whether any over-the-counter forms of the same medication exist.
This page identifies an FDA-listed package (the NDC) and reports public regulatory and pricing data about the listing. It is reference information, not a medical recommendation — talk to your pharmacist or prescriber about your own medication.
Where does this data come from?
Listing facts (marketing category, packager status, marketing dates) from the FDA openFDA NDC Directory; label availability from DailyMed; pricing coverage from CMS NADAC; equivalence scope from the FDA Orange Book.

📄 Full prescribing information FDA SPL

The complete FDA label for this product — the official prescribing information, verbatim, section by section. Jump with a chip, search within the label, or expand everything.
🎯 Indications and Usage ⏱️ Dosage and Administration 💊 Dosage Forms and Strengths ⛔ Contraindications ⚠️ Warnings and Cautions 🤒 Adverse Reactions 🔄 Drug Interactions 👥 Use in Specific Populations 🤰 Pregnancy 🧒 Pediatric Use 🧓 Geriatric Use 🆘 Overdosage 🧬 Clinical Pharmacology 🧬 Mechanism of Action 📦 How Supplied / Storage and Handling 📋 Description 💬 Information for Patients
🎯 Indications and Usage 136 words ▾

1 INDICATIONS AND USAGE Tiopronin delayed-release tablets are 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. However, due to Mission Pharmacal Company’s marketing exclusivity rights, this drug product is not labeled with that information.

Tiopronin delayed-release tablets are 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 9 years of age and older with severe homozygous cystinuria, who are not responsive to these measures alone. ( 1 )

⏱️ Dosage and Administration ~3 min read ▾

2 DOSAGE AND ADMINISTRATION The recommended initial dosage in adult patients is 800 mg/day. In clinical studies, the average dosage was about 1,000 mg/day. ( 2.1 ) The recommended initial dosage in pediatric patients 9 years of age and older is 15 mg/kg/day.

Avoid dosages greater than 50 mg/kg per day in pediatric patients . ( 5.1 , 8.4 ) Measure urinary cystine 1 month after initiation of tiopronin delayed-release tablets and every 3 months thereafter ( 2.3 ) Administer tiopronin delayed-release tablets in 3 divided doses at the same times each day, with or without food. Maintain a routine pattern with regard to meals.

( 2.1 ) Tiopronin delayed-release tablets can be crushed and mixed with applesauce. For preparation and administration instructions, see the full prescribing information. ( 2.2 )

2.1Recommended Dosage Adults : The recommended initial dosage in adult patients is 800 mg/day. In clinical studies, the average dosage was about 1,000 mg/day. Pediatrics : The recommended initial dosage in pediatric patients 9 years of age and older is 15 mg/kg/day.

Avoid dosages greater than 50 mg/kg per day in pediatric patients [see Warnings and Precautions ( 5.1 ), Use in Specific Populations ( 8.4 )]. Additional pediatric use information is approved for Mission Pharmacal Company’s Thiola EC (tiopronin) delayed release tablets. However, due to Mission Pharmacal Company’s marketing exclusivity rights, this drug product is not labeled with that information.

Administer tiopronin delayed-release tablets in 3 divided doses at the same times each day, with or without food. Maintain a routine pattern with regard to meals. Consider starting tiopronin delayed-release tablets at a lower dosage in patients with history of severe toxicity to d-penicillamine.

2.2Preparation and Administration Instructions For patients who cannot swallow the tablet whole, tiopronin delayed-release tablets can be crushed and mixed with applesauce. Administration of tiopronin delayed-release tablets with other liquids or foods has not been studied and is not recommended. Preparation and Administration of Tiopronin Delayed-Release Tablets Mixed in Applesauce For patients who can swallow semi-solid food, tiopronin delayed-release tablets can be crushed and mixed with applesauce: Crush the tiopronin delayed-release tablet in a clean pill crusher or mortar and pestle.

Always crush one tablet at a time. Measure approximately one tablespoon of applesauce and transfer it into a container with the crushed tiopronin delayed-release tablet. Mix the crushed tiopronin delayed-release tablet in the applesauce until the powder is well dispersed.

Administer the entire tiopronin delayed-release tablet-applesauce mixture to the patient’s mouth immediately. (However, if this is not possible, the mixture can be stored in a refrigerator for up to 2 hours after adding the crushed tablet to the applesauce. Discard any mixture that has not been given within 2 hours.) To assure that any leftover applesauce mixture from the container is recovered, add tap water to the same container, mix, and have the patient drink the water.

2.3Monitoring Measure urinary cystine 1 month after starting tiopronin delayed-release tablets and every 3 months thereafter. Adjust tiopronin delayed-release tablets dosage to maintain urinary cystine concentration less than 250 mg/L. Assess for proteinuria before treatment and every 3 to 6 months during treatment [see Warnings and Precautions ( 5.1 )].

Discontinue tiopronin delayed-release tablets in patients who develop proteinuria, and monitor urinary protein and renal function. Consider restarting tiopronin delayed-release tablets treatment at a lower dosage after resolution of proteinuria.

💊 Dosage Forms and Strengths 68 words ▾

3 DOSAGE FORMS AND STRENGTHS Tablets for oral use: 100 mg tablets: White to off-white round shaped biconvex tablets imprinted with “D1” on one side with red ink and plain on the other side. 300 mg tablets: White to off-white round shaped biconvex tablets imprinted with “D3” on one side with red ink and plain on the other side. Tablets: 100 mg and 300 mg ( 3 )

⛔ Contraindications 42 words ▾

4 CONTRAINDICATIONS Tiopronin delayed-release tablets are contraindicated in patients with hypersensitivity to tiopronin or any other components of tiopronin delayed-release tablets [see Warnings and Precautions ( 5.2 )] . Hypersensitivity to tiopronin or any component of tiopronin delayed-release tablets ( 4 )

⚠️ Warnings and Cautions 154 words ▾

5 WARNINGS AND PRECAUTIONS Proteinuria, including nephrotic syndrome, and membranous nephropathy, has been reported with tiopronin use. Pediatric patients receiving greater than 50 mg/kg of tiopronin per day may be at increased risk for proteinuria. ( 2.1 , 5.1 , 8.4 ) Hypersensitivity reactions have been reported during tiopronin treatment. ( 4 , 5.2 )

5.1Proteinuria Proteinuria, including nephrotic syndrome, and membranous nephropathy, have been reported with tiopronin use. Pediatric patients receiving greater than 50 mg/kg of tiopronin per day may be at increased risk for proteinuria [see Dosage and Administration ( 2.3 ), Adverse Reactions ( 6.1 , 6.2 ) Use in Specific Populations ( 8.4 )] . Monitor patients for the development of proteinuria and discontinue therapy in patients who develop proteinuria [see Dosage and Administration ( 2.3 )] .

5.2Hypersensitivity Reactions Hypersensitivity reactions (drug fever, rash, fever, arthralgia and lymphadenopathy) have been reported [see Contraindications ( 4 )] .

🤒 Adverse Reactions ~3 min read ▾

6 ADVERSE REACTIONS The following adverse reactions are discussed in greater detail in other sections of the labeling: Proteinuria [see Warnings and Precautions ( 5.1 )] Hypersensitivity [see Warnings and Precautions ( 5.2 )] Most common adverse reactions (≥10%) are nausea, diarrhea or soft stools, oral ulcers, rash, fatigue, fever, arthralgia, proteinuria, and emesis. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Par Health at 1-800-828-9393 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, the adverse reaction rates observed in the clinical trials of the drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Adverse reactions occurring at an incidence of ≥5% in an uncontrolled trial in 66 patients with cystinuria age 9 to 68 years are shown in the table below. Patients in group 1 had previously been treated with d-penicillamine; those in group 2 had not.

Of those patients who had stopped taking d-penicillamine due to toxicity (34 out of 49 patients in group 1), 22 were able to continue treatment with tiopronin. In those without prior history of d-penicillamine treatment, 6% developed reactions of sufficient severity to require tiopronin withdrawal. Table 1 presents adverse reactions ≥5% in either treatment group occurring in this trial.

Table 1: Adverse Reactions Occurring in One or More Patients Group 1 Previously treated with Group 2 Naïve to System Organ Class Adverse Reaction d-penicillamine (N = 49) d-penicillamine (N = 17) Blood and Lymphatic System Disorders anemia 1 (2%) 1 (6%) Gastrointestinal Disorders nausea 12 (25%) 2 (12%) emesis 5 (10%) – diarrhea/soft stools 9 (18%) 1 (6%) abdominal pain – 1 (6%) oral ulcers 6 (12%) 3 (18%) General Disorders and Administration Site Conditions fever 4 (8%) – weakness 2 (4%) 2 (12%) fatigue 7 (14%) – peripheral (edema) 3 (6%) 1 (6%) chest pain – 1 (6%) Metabolism and Nutrition Disorders anorexia 4 (8%) – Musculoskeletal and Connective Tissue Disorders arthralgia – 2 (12%) Renal and Urinary Disorders proteinuria 5 (10%) 1 (6%) impotence – 1 (6%) Respiratory, Thoracic and Mediastinal Disorders cough – 1 (6%) Skin and Subcutaneous Tissue Disorders rash 7 (14%) 2 (12%) ecchymosis 3 (6%) – pruritus 2 (4%) 1 (6%) urticaria 4 (8%) – skin wrinkling 3 (6%) 1 (6%) Taste Disturbance A reduction in taste perception may develop.

It is believed to be the result of chelation of trace metals by tiopronin. Hypogeusia is often self-limited.

6.2Postmarketing Experience Adverse reactions have been reported from the literature, as well as during post-approval use of tiopronin. Because the post-approval reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to tiopronin exposure. Adverse reactions reported during the postmarketing use of tiopronin are listed by body system in Table 2 .

Table 2: Adverse Reactions Reported for Tiopronin Pharmacovigilance by System Organ Class and Preferred Term System Organ Class Preferred Term Cardiac Disorders congestive heart failure Ear and Labyrinth Disorder vertigo Gastrointestinal Disorders abdominal discomfort; abdominal distension; abdominal pain; chapped lips; diarrhea; dry mouth; dyspepsia; eructation; flatulence; gastrointestinal disorder; gastroesophageal reflux disease; nausea; vomiting; jaundice; liver transaminitis General Disorders and Administration Site Conditions asthenia; chest pain; fatigue; malaise; pain; peripheral swelling; pyrexia; swelling Investigations glomerular filtration rate decreased; weight increased Metabolism and Nutrition Disorders decreased appetite; dehydration; hypophagia Musculoskeletal and Connective Tissue Disorders arthralgia; back pain; flank pain; joint swelling; limb discomfort; musculoskeletal discomfort; myalgia; neck pain…

🔄 Drug Interactions 54 words ▾

7 DRUG INTERACTIONS

7.1Alcohol Tiopronin is released faster from tiopronin delayed-release tablets in the presence of alcohol and the risk for adverse events associated with tiopronin delayed-release tablets when taken with alcohol is unknown. Avoid alcohol consumption 2 hours before and 3 hours after taking tiopronin delayed-release tablets [see Clinical Pharmacology (12.3)] .

👥 Use in Specific Populations ~3 min read ▾

8 USE IN SPECIFIC POPULATIONS Lactation: Breastfeeding is not recommended. ( 8.2 ) Geriatric: Choose dose carefully and monitor renal function in the elderly. ( 8.5 ) Additional pediatric use information is approved for Mission Pharmacal Company’s Thiola EC (tiopronin) delayed release tablets. However, due to Mission Pharmacal Company’s marketing exclusivity rights, this drug product is not labeled with that information.

8.1Pregnancy Risk Summary Available published case report data with tiopronin have not identified a drug-associated risk for major birth defects, miscarriage, or adverse maternal or fetal outcomes. Renal stones in pregnancy may result in adverse pregnancy outcomes (see Clinical Considerations). In animal reproduction studies, there were no adverse developmental outcomes with oral administration of tiopronin to pregnant mice and rats during organogenesis at doses up to 2 times a 2 grams/day human dose (based on mg/m 2 ).

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies are 2% to 4% and 15% to 20%, respectively.

Clinical Considerations Disease-associated maternal and/or embryo/fetal risk Renal stones in pregnancy may increase the risk of adverse pregnancy outcomes, such as preterm birth and low birth weight. Data Animal Data No findings of fetal malformations could be attributed to the drug in reproduction studies in mice and rats at doses up to 2 times the highest recommended human dose of 2 grams/day (based on mg/m 2 ).

8.2Lactation Risk Summary There are no data on the presence of tiopronin in either human or animal milk or on the effects of the breastfed child. A published study suggests that tiopronin may suppress milk production. Because of the potential for serious adverse reactions, including nephrotic syndrome, advise patients that breastfeeding is not recommended during treatment with tiopronin delayed-release tablets.

8.4Pediatric Use Tiopronin delayed-release tablets are indicated in pediatric patients 9 years of age and older with severe homozygous cystinuria, in combination with high fluid intake, alkali, and diet modification, for the prevention of cystine stone formation who are not responsive to these measures alone. This indication is based on safety and efficacy data from a trial in patients 9 years to 68 years of age and clinical experience . Proteinuria, including nephrotic syndrome, has been reported in pediatric patients.

Pediatric patients receiving greater than 50 mg/kg tiopronin per day may be at greater risk [see Dosage and Administration ( 2.1 , 2.3 ), Warnings and Precautions ( 5.1 ) and Adverse Reactions ( 6.1 )]. Tiopronin delayed-release tablets are not approved for use in pediatric patients weighing less than 20 kg [see Dosage and Administration ( 2.1 )] . Additional pediatric use information is approved for Mission Pharmacal Company’s Thiola EC (tiopronin) delayed release tablets.

However, due to Mission Pharmacal Company’s marketing exclusivity rights, this drug product is not labeled with that information.

8.5Geriatric Use This drug is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

🤰 Pregnancy 204 words ▾

8.1Pregnancy Risk Summary Available published case report data with tiopronin have not identified a drug-associated risk for major birth defects, miscarriage, or adverse maternal or fetal outcomes. Renal stones in pregnancy may result in adverse pregnancy outcomes (see Clinical Considerations). In animal reproduction studies, there were no adverse developmental outcomes with oral administration of tiopronin to pregnant mice and rats during organogenesis at doses up to 2 times a 2 grams/day human dose (based on mg/m 2 ).

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies are 2% to 4% and 15% to 20%, respectively.

Clinical Considerations Disease-associated maternal and/or embryo/fetal risk Renal stones in pregnancy may increase the risk of adverse pregnancy outcomes, such as preterm birth and low birth weight. Data Animal Data No findings of fetal malformations could be attributed to the drug in reproduction studies in mice and rats at doses up to 2 times the highest recommended human dose of 2 grams/day (based on mg/m 2 ).

🧒 Pediatric Use 175 words ▾

8.4Pediatric Use Tiopronin delayed-release tablets are indicated in pediatric patients 9 years of age and older with severe homozygous cystinuria, in combination with high fluid intake, alkali, and diet modification, for the prevention of cystine stone formation who are not responsive to these measures alone. This indication is based on safety and efficacy data from a trial in patients 9 years to 68 years of age and clinical experience . Proteinuria, including nephrotic syndrome, has been reported in pediatric patients.

Pediatric patients receiving greater than 50 mg/kg tiopronin per day may be at greater risk [see Dosage and Administration ( 2.1 , 2.3 ), Warnings and Precautions ( 5.1 ) and Adverse Reactions ( 6.1 )]. Tiopronin delayed-release tablets are not approved for use in pediatric patients weighing less than 20 kg [see Dosage and Administration ( 2.1 )] . Additional pediatric use information is approved for Mission Pharmacal Company’s Thiola EC (tiopronin) delayed release tablets.

However, due to Mission Pharmacal Company’s marketing exclusivity rights, this drug product is not labeled with that information.

🧓 Geriatric Use 59 words ▾

8.5Geriatric Use This drug is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

🆘 Overdosage 10 words ▾

10 OVERDOSAGE There is no information on overdosage with tiopronin.

🧬 Clinical Pharmacology ~2 min read ▾

12 CLINICAL PHARMACOLOGY

12.1Mechanism of Action The goal of therapy is to reduce urinary cystine concentration below its solubility limit. Tiopronin is an active reducing agent which undergoes thiol-disulfide exchange with cystine to form a mixed disulfide of tiopronin-cysteine. From this reaction, a water-soluble mixed disulfide is formed and the amount of sparingly soluble cystine is reduced.

12.2Pharmacodynamics The decrement in urinary cystine produced by tiopronin is generally proportional to the dose. A reduction in urinary cystine of 250 to 350 mg/day at tiopronin dosage of 1 g/day, and a decline of approximately 500 mg/day at a dosage of 2 g/day, might be expected. Tiopronin has a rapid onset and offset of action, showing a fall in cystine excretion on the first day of administration and a rise on the first day of drug withdrawal.

12.3Pharmacokinetics Absorption Tiopronin Delayed-Release Tablets When tiopronin immediate-release tablets and tiopronin delayed-release tablets single doses were given to fasted healthy subjects, the median time to peak plasma levels (T max ) was 1 (range: 0.5 to 2.1) and 3 (range: 1.0 to 6.0) hours, respectively. The peak exposure (C max ) and total exposure (AUC 0-t ) of tiopronin from tiopronin delayed-release tablets were decreased by 22% and 7% respectively compared to tiopronin immediate-release tablets. When tiopronin delayed-release tablets were administered crushed in applesauce, the median time to peak plasma levels of tiopronin (T max ) was 1 hour (range: 0.5 to 2.0) compared to 3.1 hours (range: 1.5 to 4.0) when administered as intact tiopronin delayed-release tablets.

When tiopronin delayed-release tablets were administered crushed in applesauce, the maximum concentration (C max ) and exposure (AUC 0-t ) to tiopronin were increased by 38% and 14%, respectively, compared to tiopronin delayed-release tablets administered intact. Food Effects Administration of the tiopronin delayed-release tablet with food decreases C max of tiopronin by 13% and AUC 0-t by 25% compared to tiopronin delayed-release tablets administered in a fasted state. Since the drug is dosed to effect, the study results support administration of tiopronin delayed-release tablets with or without food; administer at the same time each day with a routine pattern with regard to meals.

Elimination Excretion When tiopronin is given orally, up to 48% of dose appears in urine during the first 4 hours and up to 78% by 72 hours. Drug Interactions Alcohol An in vitro dissolution study was conducted to evaluate the impact of alcohol (5, 10, 20, and 40%) on the dose dumping of tiopronin delayed-release tablets. The study results showed that the addition of alcohol to the dissolution media increases the dissolution rate of tiopronin delayed-release tablets in the acidic media of 0.1N HCl [see Drug Interactions ( 7.1 )] .

🧬 Mechanism of Action 55 words ▾

12.1Mechanism of Action The goal of therapy is to reduce urinary cystine concentration below its solubility limit. Tiopronin is an active reducing agent which undergoes thiol-disulfide exchange with cystine to form a mixed disulfide of tiopronin-cysteine. From this reaction, a water-soluble mixed disulfide is formed and the amount of sparingly soluble cystine is reduced.

📦 How Supplied / Storage and Handling 87 words ▾

16 HOW SUPPLIED/STORAGE AND HANDLING 100 mg delayed-release tablets are white to off-white round shaped biconvex tablets imprinted with “D1” on one side with red ink and plain on the other side. Bottles of 300 NDC 0254-3034-30 300 mg delayed-release tablets are white to off-white round shaped biconvex tablets imprinted with “D3” on one side with red ink and plain on the other side. Bottles of 90 NDC 0254-3035-09 Store at 25°C (77°F); excursions permitted to 15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature].

📋 Description 125 words ▾

11 DESCRIPTION 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 molecular formula C 5 H 9 NO 3 S and a molecular weight of 163.19. In this drug product tiopronin exists as a dl racemic mixture.

Tiopronin is a white to off-white color crystalline powder, which is freely soluble in water. Each tiopronin delayed-release tablet contains 100 mg or 300 mg of tiopronin. The inactive ingredients in tiopronin delayed-release tablets include anhydrous lactose, colloidal silicon dioxide, hydroxypropyl cellulose, hydroxypropylcellulose low substitute, hypromellose, magnesium stearate, methacrylic acid and ethyl acrylate copolymer, talc, triethyl citrate.

Imprinting ink contains ammonium hydroxide, iron oxide red, propylene glycol, shellac and simethicone. Tiopronin

💬 Information for Patients 92 words ▾

17 PATIENT COUNSELING INFORMATION Administration Instructions For patients who cannot swallow the tablet whole, the tiopronin delayed-release tablets can be crushed and mixed with applesauce. See Dosage and Administration ( 2.2 ) for preparation and administration instructions. Lactation Advise women that breastfeeding is not recommended during treatment with tiopronin delayed-release tablets [see Use in Specific Populations ( 8.2 )] .

Manufactured for: Par Health USA Woodcliff Lake, NJ 07677 U.S.A. Product of India Made in India Neutral Code: TN/DRUGS/TN00002121 © 2026 Par Health, Inc. or one of its affiliates. OS3034-01-74-03 Revised: 07/2026

Source: FDA Structured Product Labeling, mirrored from DailyMed / openFDA. Prefer the government’s original formatting? View this label on DailyMed ↗
← 00254-3029-02 · Par 00254-3035-09 · Endo →
For educational and professional reference only — not medical advice. Pricing reflects published NADAC and CMS ASP (free public data) and may differ from your acquisition cost; always verify before billing or dispensing.