Tiopronin


Tiopronin is a prescription thiol drug used to control the rate of cystine precipitation and excretion in the disease cystinuria. Due to the rarity of the disorder, tiopronin falls under the classification of an orphan drug. It is somewhat similar to penicillamine in both chemistry and pharmacology.

Uses

Tiopronin is used primarily for cystinuria and is well known in the cystinuric community. Depending on the severity of a person's cystinuria, tiopronin may be taken for life, possibly starting in early childhood. The drug works by reacting with urinary cysteine to form a more soluble, disulfide linked, tiopronin-cysteine complex.
It may also be used for Wilson's disease, and has also been investigated for the treatment of arthritis, though tiopronin is not an anti-inflammatory.
Tiopronin is also sometimes used as a stabilizing agent for metal nanoparticles. The thiol group binds to the nanoparticles, preventing coagulation.

Side effects

Tiopronin may present a variety of side effects, which are broadly similar to those of D-penicillamine and other compounds containing active sulfhydryl groups. Its pharmacokinetics have been studied.

Society and culture

In the U.S., the drug was marketed by Mission Pharmacal at $1.50 per pill, but in 2014 the rights were bought by Retrophin, owned by Martin Shkreli, and the price increased to $30 per pill for a 100mg capsule.
In 2016 Imprimis Pharmaceuticals introduced a lower cost version marketed as a compounded drug.