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Thiola

Generic: tiopronin

Verified·Apr 23, 2026
Manufacturer
Travere Therapeutics
NDC
0178-0900
RxCUI
198287
Route
ORAL
ICD-10 indication
E72.04

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About Thiola

What is this medication? Thiola, which is known by the generic name tiopronin, is a prescription drug primarily used to prevent the formation of cystine kidney stones in people with a rare genetic condition called cystinuria. This condition causes high levels of the amino acid cystine to accumulate in the urine, where it can crystallize and form stones that cause pain and potential damage to the urinary tract. The medication is typically prescribed for patients who have not found success through dietary changes and increased fluid intake alone. The drug works by chemically reacting with cystine in the urine to create a compound that is much more soluble than cystine itself. By making the cystine easier to dissolve, the medication prevents it from crystallizing and growing into solid stones. Patients taking this medication are generally advised to maintain a high level of hydration and may need to monitor their urine acidity to ensure the treatment is effectively protecting their kidneys from further stone development.

Copay & patient assistance

  • Patient Copay Amount: Not Publicly Available
  • Maximum Annual Benefit Limit: Not Publicly Available
  • Core Eligibility Restrictions:
  • Program is valid only for patients with commercial or private insurance.
  • Must be a resident of the United States.
  • Not valid for patients insured by any federal or state government-funded health plan, including Medicare, Medicare Advantage, Medicaid, and TRICARE.
  • Not valid for uninsured patients.
  • Program does not replace prescription drug coverage or insurance and is not intended to substitute for coverage.
  • RxBIN, PCN, and Group numbers: Not Publicly Available

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Prescribing information

From the FDA-approved label for Thiola. Official source: DailyMed (NLM) · Label effective Sep 25, 2025

Indications and usage
1 INDICATIONS AND USAGE THIOLA 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. --------------------------------------------INDICATIONS AND USAGE----------------------------------------- THIOLA 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. (1)
Dosage and administration
2 DOSAGE AND ADMINISTRATION 2.1 Recommended Dosage 2.2 Monitoring 2.1 Recommended 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 weighing 20 kg and greater 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)]. Administer THIOLA in 3 divided doses at the same times each day at least one hour before or 2 hours after meals. Consider starting THIOLA at a lower dosage in patients with history of severe toxicity to d-penicillamine. 2.2 Monitoring Measure urinary cystine 1 month after starting THIOLA and every 3 months thereafter. Adjust THIOLA 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 THIOLA in patients who develop proteinuria, and monitor urinary protein and renal function. Consider restarting THIOLA treatment at a lower dosage after resolution of proteinuria. ------------------------------------------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 20 kg and greater is 15 mg/kg/day. Avoid dosages greater than 50 mg/kg per day in pediatric patients. (2.1, 5.1, 8.4) • Administer THIOLA in 3 divided doses at the same times each day at least one hour before or 2 hours after meals. (2.1) • Measure urinary cystine 1 month after initiation of THIOLA and every 3 months thereafter. (2.2)
Contraindications
4 CONTRAINDICATIONS THIOLA is contraindicated in patients with hypersensitivity to tiopronin or any other components of THIOLA [see Warnings and Precautions (5.2)]. ----------------------------------------------CONTRAINDICATIONS------------------------------------------ • Hypersensitivity to tiopronin or any component of THIOLA (4)
Warnings and precautions
5 WARNINGS AND PRECAUTIONS 5.1 Proteinuria 5.2 Hypersensitivity Reactions 5.1 Proteinuria 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 (2.2), 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 (2.2)]. 5.2 Hypersensitivity Reactions Hypersensitivity reactions (drug fever, rash, fever, arthralgia and lymphadenopathy) have been reported [see Contraindications (4)]. ------------------------------------------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)
Adverse reactions
6 ADVERSE REACTIONS 6.1 Clinical Trials Experience 6.2 Postmarketing Experience 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)] 6.1 Clinical 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 THIOLA. In those without prior history of d-penicillamine treatment, 6% developed reactions of sufficient severity to require THIOLA withdrawal. Table 1 presents adverse reactions ≥5% in either treatment group occurring in this trial. 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. 6.2 Postmarketing Experience Adverse reactions have been reported from the literature, as well as during post-approval use of THIOLA. 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 THIOLA exposure. Adverse reactions reported during the postmarketing use of THIOLA are listed by body system in Table 2. ---------------------------------------------ADVERSE REACTIONS------------------------------------------- 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 Mission Pharmacal Company at toll-free phone # 1-800-298-1087 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. Picture Image
Use in pregnancy
8 USE IN SPECIFIC POPULATIONS 8.1 Pregnancy 8.2 Lactation 8.4 Pediatric Use 8.5 Geriatric Use 8.1 Pregnancy 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 ). 8.2 Lactation 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 THIOLA. 8.4 Pediatric Use THIOLA is indicated in pediatric patients weighing 20 kg or more 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, 2.2), Warnings and Precautions (5.1) and Adverse Reactions (6.1)]. THIOLA tablets are not approved for use in pediatric patients weighing less than 20 kg or in pediatric patients unable to swallow tablets [see Recommended Dosage (2.1)]. 8.5 Geriatric 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. -----------------------------------------USE IN SPECIFIC POPULATIONS-------------------------------------- • Lactation: Breastfeeding is not recommended. (8.2) • Geriatric: Choose dose carefully and monitor renal function in the elderly. (8.5) See 17 for PATIENT COUNSELING INFORMATION. Revised: 01/2021

Label text is reproduced as-is from the FDA-approved label. We do not paraphrase, summarize, or omit. Content above is for informational purposes only and is not medical advice. Always consult your prescribing clinician or pharmacist before making decisions about your medication.

Conditions we've indexed resources for

Click a condition to see copay cards, grants, and PA rules specific to it. For the full list of FDA-approved indications, see Prescribing information above.

Medicare Part D coverage

How Thiola appears across Medicare Part D plan formularies nationally. Source: CMS monthly Prescription Drug Plan file (2026-04-30).

Covered by plans

2%

115 of 5,509 plans

Most common tier

Tier 5

On 100% of covering formularies

Prior authorization required

0%

of covering formularies

TierFormularies on this tierShare
Tier 5 (specialty)2
100%

Step therapy: 0% of formularies

Quantity limits: 0% of formularies

Coverage breadth: 2 of 65 formularies

How to read this:plans on the same formulary share tier + PA rules. Your specific plan's copay depends on (a) the tier above, (b) your plan's cost-share for that tier, (c) whether you're in the initial coverage phase or past the 2026 $2,000 out-of-pocket cap. For your exact plan, check its Summary of Benefits or log in to your Medicare.gov account. Copay cards don't apply to Medicare (federal law).

Prior authorization & coverage

PayerPAStep therapyCopay tier

Medicare Part D

Related drugs

How this page is sourced

  • Drug identity verified against openFDA NDC Directory.
  • Label text (when shown) originates from NLM DailyMed.
  • Copay and assistance URLs verified periodically; if you hit a broken link, tell us.

Rare-disease navigation (specialists, trials, patient communities)

Thiola treats a rare condition. For in-depth disease pages on our sister site:

UniteRare.org is our sister site for rare-disease navigation — same editorial team, same accuracy standards.