Dosing and uses of Thiola (tiopronin)
Adult dosage forms and strengths
tablet (Thiola)
- 100mg
capsule for customizable compounding (Tiopropin DR)
- 200mg
- 250mg
capsule for customizable compounding plus potassium citrate (Tiopropin-K DR)
- 150mg/2mEq
- 150mg/4mEq
- 250mg/2mEq
- 250mg/4mEq
Prevention of Nephrolithiasis
Indicated for the prevention of cystine kidney stone formation in patients with severe homozygous cystinuria with urinary cystine >500 mg/day, who are resistant to treatment with conservative measures of high fluid intake, alkali and diet modification, or who have adverse reactions to d-penicillamine
Initial: 800 mg/day PO divided three times daily
Titrate dose to maintain urinary cystine <250 mg/L (average daily dose is ~1000 mg/day)
Pediatric dosage forms and strengths
tablet (Thiola)
- 100mg
capsule for customizable compounding (Tiopropin DR)
- 200mg
- 250mg
capsule for customizable compounding plus potassium citrate (Tiopropin-K DR)
- 150mg/2mEq
- 150mg/4mEq
- 250mg/2mEq
- 250mg/4mEq
Prevention of Nephrolithiasis
Indicated for the prevention of cystine kidney stone formation in patients with severe homozygous cystinuria with urinary cystine >500 mg/day, who are resistant to treatment with conservative measures of high fluid intake, alkali and diet modification, or who have adverse reactions to d-penicillamine
<9 years: Safety and efficacy have not been established
≥9 years
- Initial: 5 mg/kg PO TID
- Titrate dose to maintain urinary cystine <250 mg/L
Thiola (tiopronin) adverse (side) effects
Frequency not defined
Fever
Skin complications
Hypersensitivity reactions
Taste and smell impairment
Generalized rash
GI symptoms
SLE-like syndrome
Hypogeusia
Skin wrinkling
Jaundice
Leukopenia
Thrombocytopenia
Aplastic anemia
Agranulocytosis
Goodpasture's syndrome
Myasthenia gravis
Warnings
Contraindications
Hypersensitivity, pregnancy (except if benefit outweighs risk), breastfeeding
History of developing tiopronin-induced agraulocystosis, aplastic anemia, thrombocytopenia (except in severe cysteinuria where benefit of inhibited stond formation outweighs risk of treatment breast feeding
Breast feeding
Cautions
Check urinary cystine frequently for first 6 months of treatment to assess efficacy, and every 6 months thereafter
Monitor CBC, Hgb, serum albumin, LFTs, 24 hr urinary protein, routine UA q3-6months
Discontinue if WBC <3500/mm³ or Platelets <100 k/mm³
ADRs are more likely to occur in patients who have shown toxicity to d-penicillamine
Risk of Goodpasture's syndrome possible (discontinue if it occurs)
Risk of myesthenia gravis possible (discontinue if it occurs)
Discontinue if pemphigus-type reaction occurs
Monitor for membranous glomerulopathy (proteinuria may develop)
Pregnancy and lactation
Pregnancy category: C
Lactation: Excretion in breast milk unknown; contraindicated
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Thiola (tiopronin)
Mechanism of action
Undergoes thiol-disulfide exchange with cystine to form a mixed disulfide of tiopronin-cysteine (more water-soluble), which in turn reduces formation of cycteine calculi
Reduces urinary cystine by 250-350 mg per 1 g drug
