Open Label Prospective Observational Registry of Thiola EC Therapy

Thiola EC represents several modifications of Thiola that promise better, more efficacious therapy of cystinuria. First, pill size has changed from 100 mg to 300 mg, meaning that typical pill burden will be reduced from, on average, 10 pills per day to 3-5 pills per day. This change will be welcomed by patients whose fluid intake and administration of potassium citrate are daily impositions. Second, the preparation is now enteric-coated, formulated to offer delayed release of active tiopronin. Lastly, Thiola EC can be taken with food which is an improvement to the inconvenient dosing regimen of Thiola, which can only be taken one hour before, or two hours after meals. These changes may affect compliance and side effect profiles compared to those of Thiola. In combination with potassium citrate or other alkali preparations, adverse GI effects are relatively common in actively-treated patients with cystinuria. It is possible that GI side effects may be reduced by Thiola EC.