Tiopronin
Tiopronin is an oral medication used to prevent cystine kidney stones in people with severe homozygous cystinuria (a rare inherited condition that causes cystine to build up in the urine).
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 10 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
📖 Tiopronin: Patient Information Guide
A plain-language walkthrough of Tiopronin — what it treats, how it works, how it’s taken, side effects, warnings and interactions. Tap any section to expand it.
🎯What it's used for▾
Tiopronin is used to prevent cystine kidney stones in people with a rare inherited condition called severe homozygous cystinuria. It is always used alongside high fluid intake, dietary changes, and alkali therapy — not as a standalone treatment.
- Thiola (tablet): prevents cystine stone formation in adults and children weighing 20 kg or more with severe homozygous cystinuria who have not responded to other measures alone.
- Tiopronin (tablet): prevents cystine stone formation in adults and children 9 years of age and older with severe homozygous cystinuria who have not responded to other measures alone.
- Thiola EC (delayed-release tablet): prevents cystine stone formation in adults and children weighing 20 kg or more with severe homozygous cystinuria who have not responded to other measures alone.
- Tiopronin (delayed-release tablet): prevents cystine stone formation in adults and children 9 years of age and older with severe homozygous cystinuria who have not responded to other measures alone.
- Venxxiva (delayed-release tablet): prevents cystine stone formation in adults and children 9 years of age and older with severe homozygous cystinuria who have not responded to other measures alone.
⚙️How it works▾
In cystinuria, the kidneys excrete too much cystine — an amino acid that barely dissolves in urine. When cystine concentration gets too high, it crystallizes and forms hard stones in the kidneys or urinary tract. Tiopronin works by chemically reacting with cystine through a process called thiol-disulfide exchange, converting it into a new compound — a tiopronin-cysteine complex — that is water-soluble and can be easily flushed out in the urine. The end result is a lower concentration of hard-to-dissolve cystine in the urine, which reduces the chance of stone formation.
💊How it's taken▾
All tiopronin products are taken by mouth in three divided doses per day, ideally at the same times each day. The timing around meals differs by product:
- Thiola (tablet) and Tiopronin (tablet): take at least 1 hour before or 2 hours after meals.
- Thiola EC (delayed-release tablet) and Tiopronin (delayed-release tablet): may be taken with or without food — keep a consistent routine with meals.
- Venxxiva (delayed-release tablet): take without food.
Your doctor will check your urine cystine levels 1 month after starting and every 3 months thereafter to make sure the dose is working. Never adjust your dose on your own.
🤒Side effects — in detail▾
The most common side effects of tiopronin include:
- Nausea, vomiting, or diarrhea
- Mouth sores (oral ulcers)
- Rash, itching, or hives
- Fatigue or weakness
- Fever
- Joint pain
- Swelling
- Reduced or altered sense of taste — this is often temporary
More seriously, tiopronin can cause protein to leak into the urine (proteinuria), which in rare cases can progress to a serious kidney condition. Contact your doctor immediately if you notice foamy urine, significant swelling, or signs of an allergic reaction such as fever, rash, swollen lymph nodes, or joint pain.
⚠️Warnings & precautions▾
- Proteinuria and kidney disease: Tiopronin can cause protein to appear in the urine (proteinuria), and in some cases this progresses to nephrotic syndrome or membranous nephropathy — serious kidney conditions. Your doctor will test your urine for protein before you start and periodically during treatment. If proteinuria develops, tiopronin must be stopped, and your kidney function will be monitored.
- Children at higher risk: Pediatric patients receiving more than 50 mg/kg per day of tiopronin may face an increased risk of proteinuria. Doses in children are carefully weight-based and capped.
- Hypersensitivity reactions: Some people develop drug fever, rash, fever, joint pain (arthralgia), or swollen lymph nodes. These can be signs of a serious reaction — tell your doctor right away.
- History of d-penicillamine toxicity: People who had severe reactions to d-penicillamine may also react to tiopronin and should start at a lower dose.
🔀What it interacts with▾
There is one important interaction to be aware of with tiopronin delayed-release tablets:
- Alcohol: Drinking alcohol within 2 hours before or 3 hours after taking tiopronin delayed-release tablets (Thiola EC, Tiopronin delayed-release, or Venxxiva) can cause the medication to release into your body much faster than intended. This "dose dumping" effect raises the risk of adverse effects. Avoid alcohol during that window.
This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.
📋Before taking it▾
- Allergy: Do not take tiopronin if you are allergic to tiopronin or any ingredient in your specific product.
- Kidney problems: Tiopronin is mainly cleared by the kidneys. People with reduced kidney function are at greater risk for side effects and need close monitoring.
- Older adults: Kidney function often declines with age, so elderly patients should be monitored carefully and doses chosen with care.
- Pregnancy: Available data have not identified a clear risk of birth defects, but untreated kidney stones in pregnancy can lead to complications such as preterm birth or low birth weight. Discuss the risks and benefits with your doctor.
- Breastfeeding: Breastfeeding is not recommended during tiopronin treatment. There are no safety data for infants exposed through breast milk, and tiopronin may suppress milk production.
- Children: Use in children is approved only for those meeting the weight or age criteria specific to each product. Tiopronin tablets (Thiola and Tiopronin brand) are not approved for children weighing less than 20 kg or those who cannot swallow tablets.
- Prior d-penicillamine reactions: Tell your prescriber if you had severe side effects from d-penicillamine — a lower starting dose of tiopronin may be recommended.
📡Pharmacodynamics — effects in the body▾
Tiopronin lowers the concentration of cystine in the urine, and the amount of reduction is generally proportional to the dose. At higher doses, more cystine is cleared from the urine each day. The effect is fast-acting in both directions: cystine excretion drops on the very first day of treatment and rises again on the first day after stopping the medication.
🔬Pharmacokinetics — how your body processes it▾
When tiopronin delayed-release tablets are taken on an empty stomach, the medication reaches peak blood levels in about 3 hours — slower than the immediate-release tablet, which peaks in about 1 hour. Taking delayed-release tablets with food lowers the peak level and overall absorption somewhat, but since the dose is adjusted based on how well it works (urine cystine levels), these variations are generally manageable; consistent timing with meals is what matters most. Once absorbed, tiopronin is substantially eliminated through the urine — up to 48% of a dose appears in urine within the first 4 hours, and up to 78% within 72 hours.
📦How to store it▾
Store at 25°C (77°F); excursions permitted between 15°C and 30°C (59°F and 86°F) .
📄 Written from Tiopronin’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Every point is grounded in that labeling — nothing is invented. How we use AI →
🩺 Pharmacist Counseling Corner
Quick, plain-English answers to the questions patients ask most about Tiopronin — the kind of thing our pharmacy team would talk through with you at the counter.
What exactly is tiopronin used for? ▾
How should I take my tiopronin — with or without food? ▾
What side effects should I watch for? ▾
Can I drink alcohol while taking tiopronin? ▾
Will I need regular blood or urine tests while on this medication? ▾
Is tiopronin safe during pregnancy or while breastfeeding? ▾
Is Tiopronin available over the counter? ▾
When was Tiopronin first available? ▾
Who makes Tiopronin? ▾
💬 Answers drafted from Tiopronin’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Grounded in that labeling — nothing is made up. How we use AI →
🧰 Keep exploring
💊 How Tiopronin comes
Tiopronin is available in 2 forms. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Delayed-release tablet
How this form is used
- Thiola EC is used to prevent cystine kidney stones in adults and children weighing 20 kg or more with severe homozygous cystinuria, when other measures alone have not worked.
- Tiopronin delayed-release tablets are used to prevent cystine kidney stones in adults and children 9 years of age and older with severe homozygous cystinuria, when other measures alone have not worked.
- Venxxiva is used to prevent cystine kidney stones in adults and children 9 years of age and older with severe homozygous cystinuria, when other measures alone have not worked.
- Thiola EC and Tiopronin delayed-release tablets may be taken with or without food — but take them at the same times each day and keep a consistent routine with meals.
- Venxxiva is taken without food, in 3 divided doses at the same times each day.
- Thiola EC and Tiopronin delayed-release tablets can be crushed and mixed with approximately one tablespoon of applesauce for patients who cannot swallow whole tablets — do not mix with other foods or liquids.
- Avoid alcohol within 2 hours before or 3 hours after taking any delayed-release tiopronin product, as alcohol can cause the medication to release too fast.
Tablet
How this form is used
- Thiola (tablet) is used to prevent cystine kidney stones in adults and children weighing 20 kg or more with severe homozygous cystinuria, when other measures alone have not worked.
- Tiopronin tablets are used to prevent cystine kidney stones in adults and children 9 years of age and older with severe homozygous cystinuria, when other measures alone have not worked.
- Thiola tablets are taken in 3 divided doses each day, at least 1 hour before or 2 hours after meals.
- Tiopronin tablets are taken in 3 divided doses each day, at least 1 hour before or 2 hours after meals.
- Take at the same times each day and maintain a consistent routine around meals.
- Your doctor will check your urine cystine level 1 month after starting and every 3 months after that.
📊 Tiopronin across the U.S. market
How Tiopronin appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
FDA-listed product records by dose form (tablet variants merged) — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
Also listed with the FDA, not a patient dose form: Powder (6) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.
Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
📈 How widely Tiopronin is used
A general measure of how commonly Tiopronin is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Tiopronin is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Tiopronin prescribed? Of the 1,596 medications we measure, Tiopronin ranks #1,351 by Medicaid prescriptions — more than 15% of them.
Utilization by Tiopronin product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
tiopronin 300 MG Delayed Release Oral Tablet Most dispensed
Summed across the 1 of 7 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2178079
tiopronin 100 MG Delayed Release Oral Tablet
Summed across the 1 of 6 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2178075
tiopronin 100 MG Oral Tablet
Summed across the 1 of 2 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 198287
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Tiopronin, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 3 of 15 listed Tiopronin NDCs with Medicaid activity.
🔍 Compare Tiopronin products
A representative set of FDA-listed product records for Tiopronin — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Delayed-release tablet | ||||
| 300 mg | Oral | Amneal Pharmaceuticals NY LLC × 2 listings | ANDA | View NDC → |
| 100 mg | Oral | BioComp Pharma, Inc. | NDA AUTHORIZED GENERIC | View NDC → |
| 300 mg | Oral | BioComp Pharma, Inc. | NDA AUTHORIZED GENERIC | View NDC → |
| 100 mg | Oral | Cycle Pharmaceuticals Ltd. | ANDA | View NDC → |
| 300 mg | Oral | Cycle Pharmaceuticals Ltd. | ANDA | View NDC → |
| 100 mg | Oral | Endo USA, Inc. | ANDA | View NDC → |
| 300 mg | Oral | Endo USA, Inc. | ANDA | View NDC → |
| 100 mg | Oral | Mission Pharmacal Company × 3 listings | NDA | View NDC → |
| 300 mg | Oral | Mission Pharmacal Company × 3 listings | NDA | View NDC → |
| 100 mg | Oral | Par Health USA, LLC | ANDA | View NDC → |
| 300 mg | Oral | Par Health USA, LLC | ANDA | View NDC → |
| 100 mg | Oral | Teva Pharmaceuticals, Inc. × 2 listings | ANDA | View NDC → |
| 300 mg | Oral | Teva Pharmaceuticals, Inc. × 2 listings | ANDA | View NDC → |
| 100 mg | Oral | Torrent Pharmaceuticals Limited | ANDA | View NDC → |
| 300 mg | Oral | Torrent Pharmaceuticals Limited | ANDA | View NDC → |
| 💊Tablet | ||||
| 100 mg | Oral | BioComp Pharma, Inc. | NDA AUTHORIZED GENERIC | View NDC → |
| 100 mg | Oral | Mission Pharmacal Company × 4 listings | NDA | View NDC → |
| 100 mg | Oral | Teva Pharmaceuticals USA, Inc. × 3 listings | ANDA | View NDC → |
| 100 mg | — | Teva Pharmaceuticals USA, Inc. | DRUG FOR FURTHER PROCESSING | View NDC → |
| 💊Bulk drug substance | ||||
| 25 kg/25 kg | — | Azico Biophore India Private Limited | BULK INGREDIENT | View NDC → |
| 1 kg/kg | — | Dasami Lab Private Limited | BULK INGREDIENT | View NDC → |
| 1 kg/kg | — | MSN Life Sciences Private Limited | BULK INGREDIENT | View NDC → |
| 35 kg/35 kg | — | Nuray Chemicals Private Limited | BULK INGREDIENT | View NDC → |
| 1 kg/kg | — | Porton Pharma Solutions Ltd | BULK INGREDIENT | View NDC → |
| 1 kg/kg | — | SCL Lifesciences Limited | BULK INGREDIENT | View NDC → |
Showing 37 of 37 products — FDA National Drug Code Directory. See every product, package size and price: browse all 37 Tiopronin NDCs →
📈 What people report — real-world data (FDA FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Tiopronin — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Tiopronin in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
🏛️ The road to your pharmacy
How Tiopronin went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
🚨 Recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
Source: openFDA drug enforcement (recall) reports.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 6765 2 dose forms · 4 strengths
-
Dose form (SCDF) Delayed Release Oral Tablet RxCUI 2178074In current FDA listings -
Dose form (SCDF) Oral Tablet RxCUI 384640In current FDA listings
Look up RxCUI 6765 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
📦 Supply & shortage status
Whether Tiopronin is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
🏷️ Sold under these brand names
🏭 Manufacturers & labelers
RxNorm drug class
Tiopronin belongs to the Reducing and Complexing Thiol class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
🔬 Where this comes from
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How we combine label and product data
HelloPharmacist combines public FDA and NLM records; we don’t author the underlying clinical facts. We identified 10 FDA-filed SPL label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. The representative label is the starting point for the displayed reference monograph; the 12 largest stored in-scope SPL records, which may include that representative, are compared section by section, and the longest available version of each section is retained. Forms, routes, brands, labelers, product-listed strengths, and product-record counts are aggregated separately from ingredient-matched FDA NDC Directory records; package records listed above are associated with the linked SPL; and the normalized concept hierarchy comes from NLM RxNorm.
For canonical ingredient pages, bounded product-attributed indication and administration excerpts may be added to the AI evidence, and the generator is instructed to preserve available product, brand, route, and form qualifiers instead of treating one label as universal. Where a section is identified as AI-written, its plain-language text is generated from bounded label evidence. New draft drug pages remain in the admin review queue before first publication. Mission Pharmacal Company is the representative DailyMed label linked for verification and dates; it is not the sole source used for the page.
This is general education, not medical advice — always consult your doctor or pharmacist about your medications and any medical condition. For the exact wording of the linked representative label, view that label on DailyMed; some displayed composite sections may come from other in-scope SPL labels. Learn how we use AI and our data sources & update cadence.