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Tiopronin
Published in Anton C. de Groot, Monographs in Contact Allergy, 2021
Tiopronin is an acylated sulfhydryl-containing derivative of glycine with reducing and complexing properties. It breaks the disulfide bond of cystine (an oxidized dimeric form of cysteine) and binds the sulfhydryl group of the resultant cysteine monomers to form a soluble tiopronin-cysteine-mixed disulfide, which is more water-soluble than cystine and is readily excreted. This leads to a reduction in urinary cystine concentration and subsequently reduces cystine stone formation. Tiopronin is indicated as a second-line for the prevention of kidney stone formation in patients with severe homozygous cystinuria. This drug may also be used as a mucolytic drug and to bind metal nanoparticles in Wilson’s disease, which is an overload of copper in the body (1,2).
Urolithiasis
Published in Manit Arya, Taimur T. Shah, Jas S. Kalsi, Herman S. Fernando, Iqbal S. Shergill, Asif Muneer, Hashim U. Ahmed, MCQs for the FRCS(Urol) and Postgraduate Urology Examinations, 2020
Thomas Johnston, James Armitage, Oliver Wiseman
D-Penicillamine may be used to treat cystinuria. It binds to cystine forming a disulphide complex that is 50 times more soluble than cystine. Side effects are common affecting approximately 50% of patients. They include nausea, arthralgia, loss of taste and rash. Leukopaenia and thrombocytopaenia are also recognised side effects and bloods should therefore be checked every 1–2 weeks initially then every 4 weeks. Tiopronin (Thiola®) is a complexing thiol compound with similar side effects to penicillamine, although these occur much less commonly.
What are the main challenges to the pharmacological management of cystinuria?
Published in Expert Opinion on Pharmacotherapy, 2020
Michael E. Rezaee, Andrew D. Rule, Vernon M. Pais
Per AUA guidelines, second-line therapy for cystinuria consists of thiol medications that disrupt the disulfide bond between cysteine molecules and bind cysteine directly, ultimately increasing its solubility in the urine [6]. α-mercaptopropionyl glycine (tiopronin) is a second-generation thiol drug that is preferentially prescribed for cystinuria due to its perceived less toxic side effects. Tiopronin has been shown to successfully prevent stone formation in 70% of cystinuria patients [7]. Approximately 65% of patients taking tiopronin will experience side effects, but less than 1/3 of these patients will stop the medication due to an adverse drug reaction [7]. Common dosing for tiopronin is 800–1,000 mg/day divided into three doses taken one hour before or two hours after meals; this has historically equated to 8 to 10 100mg tablets per day for patients [8]. An enteric-coated formulation of tiopronin was recently released in 2019 in 100mg and 300mg tablet-form [9]. This formulation can be taken irrespective of food consumption and substantially reduces the number of pills taken by patients [9].
Established and recent developments in the pharmacological management of urolithiasis: an overview of the current treatment armamentarium
Published in Expert Opinion on Pharmacotherapy, 2020
Mohamed Abou Chakra, Athanasios E. Dellis, Athanasios G. Papatsoris, Mohamad Moussa
In patients who are refractory to increased fluid intake, urinary alkalinization and dietary restriction of protein and salt, cystine-binding thiol drugs are recommended. Drugs most commonly used include d-penicillamine, α-mercaptopropionyl glycine (tiopronin). These drugs have the ability to dissociate the cystine molecule into disulfide moieties with much higher solubility. Tiopronin was equally as effective as D-penicillamine in reducing cystine excretion but with much less serious adverse reactions [121]. Tiopronin dose starting at 800 mg/day divided into two or three times daily. The dosage should be readjusted depending on the urinary cystine value to achieve a urine cystine concentration of less than 250 mg/L. Adverse effects of tiopronin usage include fever, asthenia, rash, joint aches, loss of taste, thrombocytopenia, aplastic anemia, proteinuria [122].
Why is diagnosis, investigation, and improved management of kidney stone disease important? Non-pharmacological and pharmacological treatments for nephrolithiasis
Published in Expert Review of Clinical Pharmacology, 2022
Viola D’Ambrosio, Shabbir Moochhala, Robert J Unwin, Pietro Manuel Ferraro
Despite the progress that has been made in understanding many important aspects of the pathogenesis of kidney stone disease, advances in its pharmacological treatment have, in contrast, been limited, apart from the rare example of inherited primary hyperoxaluria. The basis of drug therapy in those with a history of recurrent calcium-containing stones is the almost universal prescribing of potassium citrate (sodium citrate or bicarbonate may increase sodium excretion) to supplement the dietary recommendations discussed earlier, especially when citrate excretion is low, and a thiazide diuretic in patients with increased calcium excretion (Table 2). As already mentioned, citrate is a potent inhibitor of calcium stone formation and hypocitraturia is a common finding in nephrolithiasis. Moreover, drugs such as the anticonvulsant topiramate, which can inhibit carbonic anhydrase, by reducing citrate excretion and simultaneously increasing urinary pH, increase the risk of calcium phosphate stone formation [69]. Several small clinical trials have shown that modest doses of thiazide diuretics can reduce stone formation, especially when dietary sodium intake is also restricted [70]; however, diuretic-induced potassium losses may offset any benefit by reducing citrate excretion, and so co-prescription with a potassium supplement (citrate or chloride) is usually recommended. The two main therapies for uric acid stone are, still today, proper hydration and urinary alkalization to increase uric acid solubility in the urine. According to the AUA guidelines, the xanthine oxidase inhibitor, allopurinol, should be administered in hyperuricosuric patients with recurrent calcium oxalate stones and no hypercalciuria [1]. proper hydration and urinary alkalization are also part of the first-line management of cystine stones in patients with cystinuria, although a cystine-binding thiol such as d-penicillamine or tiopronin (which may have fewer adverse effects) may also be prescribed, especially when hydration, dietary recommendation, and alkali supplementation is not sufficient in halting stone formation. Current drug treatment options are summarized in Table 3.