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Prior authorization coverage for oral tiopronin products used to prevent cystine stone formation in adults and pediatric members with severe homozygous cystinuria, including initial and continuation criteria, documentation requirements, age restrictions, quantity limits, and pharmacy self-administration.
Policy Summary
PayerMolina Healthcare
PolicyThiola (tiopronin) Coverage Criteria
Policy CodePolicy C18004-A
Change TypeNo material change
Effective DateAug 30, 2026
Next Review DateJul 1, 2027
Key ActionSubmit prior authorization documentation showing severe homozygous cystinuria, member weight of at least 20 kg, required treatment trials, prescriber qualifications, age eligibility, and requested quantity.
No material clinical or coverage changes in this revision.
20 kgMinimum member weight
12 monthsAuthorization duration
85%Continuation adherence
<250 mg/LTarget urinary cystine
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Coverage Criteria
Initial Therapy
Covered when ALL of the following initial therapy criteria are met.
Initial therapy
Diagnosis and confirmation
Diagnosis
Member has a documented diagnosis of severe homozygous cystinuria.
ONE of the following confirmatory methods
Stone analysis shows cysteine.
Family history of cystinuria is positive.
Pathognomonic hexagonal cystine crystals are identified on urinalysis.
Cyanide-nitroprusside screen is positive.
Weight and baseline disease burden
Member weighs at least 20 kg.≥20 kg
Baseline urinary cystine concentration is greater than 500 mg/day.>500 mg/day
Failure of conservative measures
Fluid and dietary modification
Member has completed a 30-day trial with increased fluid intake, sodium restriction, and protein restriction.30 days
Failure demonstrated by ONE of the following
Urine cystine concentration cannot be reduced below 250 mg/L and urine pH cannot be raised above 7 in a 24-hour urine.urine cystine <250 mg/L and urine pH >7
Urinary cystine supersaturation cannot be reduced below 1, when measured.<1 when measured
Prior tiopronin safety
Member does not have a history of agranulocytosis, aplastic anemia, or thrombocytopenia from previous tiopronin use.
Continuation Therapy
Covered for continuation when ALL of the following criteria are met.
Continuation therapy
Adherence
Adherence is at least 85%, as verified by the prescriber or member medication fill history.≥85%
Adherence is less than 85% because surgery or treatment of an infection required temporary discontinuation.<85% only for a qualifying temporary interruption
Positive response
Urinary cystine concentration is below 250 mg/L.<250 mg/L
Initial Therapy
Covered when ALL of the following criteria are met.
Initial therapy
Member has severe homozygous cystinuria.
Member is an adult or pediatric patient weighing at least 20 kg (44 lb).≥20 kg (44 lb)
High fluid intake, alkali, and dietary modification alone have not produced an adequate response.
Thiola/Thiola EC will be used in combination with high fluid intake, alkali, and dietary modification to prevent cystine stone formation.
Continuation is excluded if the member develops hypersensitivity, agranulocytosis, aplastic anemia, thrombocytopenia, renal complications of proteinuria or nephrotic syndrome, Goodpasture syndrome, myasthenia gravis or myasthenic syndrome, or a pemphigus-type reaction. Therapy should be discontinued if proteinuria develops; after proteinuria resolves, resumption may be considered at a lower dose.
Thiola/Thiola EC is contraindicated in members with hypersensitivity to tiopronin or any other component of the medication.
Uses other than prevention of cystine stone formation in the covered population are considered experimental or investigational and are subject to Molina’s Off-Label policy.
Thiola/Thiola EC cannot be crushed or chewed. Therefore, these products cannot be used in pediatric members who are unable to swallow pills.
Breastfeeding is not recommended because tiopronin can decrease prolactin concentrations, which may decrease milk production.
Clinical Thresholds and Dose Parameters
Minimum Member Weight
Minimum member weightAt least 20 kg
Equivalent weightAt least 44 lb
Applicable populationAdults and pediatric patients with severe homozygous cystinuria
Baseline Urinary Cystine
Baseline urinary cystine>500 mg/day
Measurement pointBaseline assessment before therapy
DocumentationBaseline urinary cystine concentration must be documented
Authorization and Documentation Requirements
Prior Authorization
Initial Prior Authorization Required
Prior authorization is required for Thiola/Thiola EC (tiopronin). Submit the requested product, diagnosis, member-specific dosing and weight information, required clinical documentation, and evidence that all coverage criteria are met.
Document the applicable product and strength, including age-specific restrictions and quantity limits.
Include diagnosis confirmation, baseline and follow-up urinary measures, treatment history, prescriber credentials, and consultation notes when applicable.
Initial authorization is approved for 12 months when criteria are met.
Documentation Required
Annual Reauthorization Documentation
Reauthorization requires updated clinical documentation after the initial 12-month authorization and at each subsequent 12-month renewal.
Clinical Background
Tiopronin is used with high fluid intake, alkali, and dietary modification to prevent cystine stone formation in members with severe homozygous cystinuria. Coverage applies to adults and pediatric members weighing at least 20 kg (44 lb) when these measures alone are insufficient.
Policy Definitions
Failure of Conservative Management
Urinary cystine criterionFailure is inability to lower urine cystine below 250 mg/L
Urine pH criterionFailure is inability to raise urine pH above 7 in a 24-hour urine
Supersaturation or urinalysis criterionFailure is inability to lower urinary cystine supersaturation below 1 when measured, or persistence of cystine crystals on urinalysis
Initial Therapy Decision Logic
Initial Therapy
Initial therapy requires ALL of the following criteria.
Initial therapy
Member has a documented diagnosis of severe homozygous cystinuria.
ONE or more qualifying confirmation methods
Stone analysis shows cysteine.
Family history of cystinuria is positive.
Pathognomonic hexagonal cystine crystals are identified on urinalysis.
Continuation and Safety Monitoring
Continuation Therapy
Continuation requires ALL criteria below, with either qualifying adherence pathway and either qualifying response pathway.
Continuation therapy
Adherence
Adherence is at least 85%, as verified by the prescriber or member medication fill history.≥85%
Adherence is less than 85% because surgery or treatment of an infection caused temporary discontinuation.<85% only for a qualifying temporary interruption
Response
Required Conservative Treatment Steps
Step
Required therapy
Duration
Failure criteria
1
Increased fluid intake, sodium restriction, and protein restriction
30 days
Inability to lower urine cystine below 250 mg/L and raise urine pH above 7 in a 24-hour urine; inability to lower urinary cystine supersaturation below 1 when measured; or persistent cystine crystals on urinalysis
Step
Required therapy
Duration
Failure criteria
2
Urinary alkalization with potassium citrate or potassium bicarbonate, unless contraindicated
30 days
Inability to lower urine cystine below 250 mg/L and raise urine pH above 7 in a 24-hour urine; inability to lower urinary cystine supersaturation below 1 when measured; or persistent cystine crystals on urinalysis
Required supportive measures
Timing
Coverage requirement
High fluid intake, alkali, and dietary modification
Before and during Thiola/Thiola EC therapy
Use in combination with Thiola/Thiola EC for prevention of cystine stone formation when these measures alone are inadequate
Product Quantity Limits
Quantity Limit
ProductTiopronin 100 mg
30-day quantity limit900 tablets per 30 days
Dosage form100 mg tablets
Quantity Limit
ProductTiopronin delayed release 100 mg
30-day quantity limit900 tablets per 30 days
Dosage form100 mg delayed-release tablets
Pharmacy Benefit and Self-Administration
Billing Rule
Use the pharmacy benefit for home self-administration
Oral medications are recommended for pharmacy benefit coverage and patient self-administration at home.
Policy Summary
PayerMolina Healthcare
PolicyThiola (tiopronin) Coverage Criteria
Policy CodePolicy C18004-A
Change TypeNo material change
Effective DateAug 30, 2026
Next Review DateJul 1, 2027
Key ActionSubmit prior authorization documentation showing severe homozygous cystinuria, member weight of at least 20 kg, required treatment trials, prescriber qualifications, age eligibility, and requested quantity.
Cystine crystals persist on urinalysis, indicating that the urine is supersaturated with cystine.
Urinary alkalization
Member has completed a 30-day trial and failed urinary alkalization with potassium citrate or potassium bicarbonate.30 days
Urinary alkalization with potassium citrate or potassium bicarbonate is contraindicated according to the labeled contraindication.
Cystine stone production has decreased.
Member continues to increase fluid intake, restrict sodium intake, and restrict protein intake.
Prescriber attests, or clinical review establishes, that the member has not developed a contraindication or significant adverse drug effect that may exclude continued use, including hypersensitivity reaction, agranulocytosis, aplastic anemia, thrombocytopenia, renal complications of proteinuria or nephrotic syndrome, Goodpasture syndrome, myasthenia gravis or myasthenic syndrome, or a pemphigus-type reaction.
Dose adjustmentDose is adjusted to maintain urinary cystine below 250 mg/L
Target Urine pH
Target urine pH>7
Collection periodMeasured in a 24-hour urine
Failure criterionFailure is inability to raise urine pH above 7 in a 24-hour urine
Target Urinary Cystine Supersaturation
Target urinary cystine supersaturation<1
ApplicabilityUsed when the measurement is available
Failure criterionFailure is inability to lower urinary cystine supersaturation below 1
Pediatric Dose Limit
Pediatric maximum dose50 mg/kg/day
Risk thresholdDoses greater than 50 mg/kg/day should be avoided because of proteinuria risk
Recommended initial pediatric dosage15 mg/kg/day for members weighing at least 20 kg
Urinary Cystine Concentration
Target urinary cystine concentration<250 mg/L
Continuation responseA concentration below 250 mg/L qualifies as a positive response
Treatment purposeTherapy is dose-adjusted to maintain urinary cystine below 250 mg/L
Minimum Member Weight
Minimum weight≥20 kg
Pound equivalent44 lb
Covered populationAdults and pediatric members with severe homozygous cystinuria
Pediatric Proteinuria Risk
Proteinuria-risk dosage threshold≥50 mg/kg/day
Pediatric safety directionAvoid dosages greater than 50 mg/kg/day
Required action if proteinuria developsDiscontinue Thiola/Thiola EC; resumption at a lower dose may be considered after proteinuria resolves
Document adherence of at least 85% or explain a temporary interruption for surgery or infection.
Document positive response, including urinary cystine concentration below 250 mg/L or reduced cystine stone production.
Document continued fluid, sodium, and protein modification and absence of contraindications or significant adverse effects.
Submit consultation notes with each reauthorization request when prescribed in consultation with a urologist or nephrologist.
Prior Authorization
Required Clinical Indication
Thiola/Thiola EC is covered for prevention of cystine stone formation in adults and pediatric members weighing at least 20 kg who have severe homozygous cystinuria and are not responsive to high fluid intake, alkali, and dietary modification alone.
The requested use must be consistent with the FDA-approved indication.
Combination therapy with high fluid intake, urinary alkalization, and diet modification is required.
All other uses are considered experimental/investigational and follow Molina’s Off-Label policy.
Step Therapy
Diet and Fluid Modification Required
Before requesting Thiola/Thiola EC, document a compliant 30-day trial of increased fluid intake, sodium restriction, and protein restriction, with failure to adequately control cystine-related urinary findings.
Failure means inability to reduce urine cystine concentration below 250 mg/L and raise urine pH above 7 in a 24-hour urine collection, or failure to reduce urinary cystine supersaturation below 1 when measured.
Persistent cystine crystals on urinalysis also establish failure.
Document the treatment dates, compliance, and objective urine results.
Unsupported block type: step_therapy
Unsupported block type: documentation
Unsupported block type: documentation
Unsupported block type: prior_auth
Unsupported block type: documentation
Unsupported block type: step_therapy
Unsupported block type: documentation
Unsupported block type: documentation
Unsupported block type: denial_risk
Unsupported block type: denial_risk
Unsupported block type: denial_risk
Unsupported block type: prior_auth
Unsupported block type: billing_rule
Denial Risk
Indication, Weight, or Prerequisite Therapy Not Met
Deny or redirect the request when the member does not have severe homozygous cystinuria, does not weigh at least 20 kg, or has not demonstrated failure of required fluid, diet, and alkali measures.
The requested use must be prevention of cystine stone formation due to severe homozygous cystinuria.
The member must be at least 20 kg (44 lb).
The indication requires use with high fluid intake, alkali, and dietary modification.
Unsupported block type: denial_risk
Unsupported block type: denial_risk
Cyanide-nitroprusside screen is positive.
Member weighs at least 20 kg.≥20 kg
Baseline urinary cystine concentration is greater than 500 mg/day.>500 mg/day
Conservative therapy failure or contraindication
Member has completed a 30-day trial with increased fluid intake, sodium restriction, and protein restriction, with failure demonstrated by inability to reduce urine cystine below 250 mg/L and raise urine pH above 7 in a 24-hour urine, inability to reduce urinary cystine supersaturation below 1 when measured, or persistence of cystine crystals on urinalysis.30 days; urine cystine <250 mg/L, urine pH >7, supersaturation <1 when measured, or no persistent crystals
ANY of the following
Member has completed a 30-day trial and failed urinary alkalization with potassium citrate or potassium bicarbonate.30 days
Urinary alkalization with potassium citrate or potassium bicarbonate is contraindicated according to the labeled contraindication.
Member does not have a history of agranulocytosis, aplastic anemia, or thrombocytopenia from previous tiopronin use.
Initial Therapy
Initial therapy is covered when ALL of the following criteria are met.
Initial coverage criteria
Member has severe homozygous cystinuria.
Member weighs at least 20 kg (44 lb).≥20 kg (44 lb)
Member has not responded adequately to high fluid intake, alkali, and dietary modification alone.
Thiola/Thiola EC will be used in combination with high fluid intake, alkali, and dietary modification for the prevention of cystine stone formation.
Urinary cystine concentration is below 250 mg/L.<250 mg/L
Cystine stone production has decreased.
Member continues to increase fluid intake, restrict sodium intake, and restrict protein intake.
Prescriber attests, or clinical review establishes, that the member has not developed a contraindication or other significant adverse drug effect that may exclude continued use, including hypersensitivity reaction, agranulocytosis, aplastic anemia, thrombocytopenia, renal complications of proteinuria or nephrotic syndrome, Goodpasture syndrome, myasthenia gravis or myasthenic syndrome, or a pemphigus-type reaction.
Proteinuria Monitoring
Continuation or resumption requires ongoing clinical appropriateness and safety monitoring.
Proteinuria monitoring
Discontinue Thiola/Thiola EC if the member develops proteinuria.
After proteinuria has resolved, resumption of Thiola/Thiola EC may be considered at a lower dose.Proteinuria resolved before resumption