Tienilic acid

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Tienilic acid
Systematic (IUPAC) name
2-[2,3-dichloro-4-(thiophene-2-carbonyl)phenoxy]acetic acid
Identifiers
CAS number 40180-04-9
ATC code C03CC02
PubChem 38409
Chemical data
Formula C13H8Cl2O4S 
Mol. mass 331.17 g/mol
SMILES eMolecules & PubChem
Pharmacokinetic data
Bioavailability  ?
Protein binding 95%
Metabolism Hepatic
Half life 6 hours
Excretion Renal and biliary
Therapeutic considerations
Pregnancy cat.

?

Legal status

Withdrawn

Routes Oral

Tienilic acid (INN and BAN) or ticrynafen (USAN) is a diuretic drug with uric acid-lowering (uricosuric) action, formerly marketed for the treatment of hypertension. It was withdrawn in 1982, shortly after its introduction to the market, after case reports in the United States indicated a link between the use of ticrynafen and hepatitis.[1]

Tienilic acid was found to act as a suicide substrate at the cytochrome P450 enzymes involved in drug metabolism. Unfortunately, the metabolic reaction carried out by these enzymes converted tienilic acid to a thiophene sulfoxide which proved highly electrophilic. This encouraged a Michael reaction leading to alkylation of a thiol group in the enzyme's active site. Loss of water from the thiophene sulfoxide restored the thiophene ring and resulted in tienilic acid being covalently linked to the enzyme, thus inhibiting the enzyme irreversibly.

[edit] References

  1. ^ Manier JW, Chang WW, Kirchner JP, Beltaos E (1982). Hepatotoxicity associated with ticrynafen – a uricosuric diuretic. Am J Gastroenterol 77 (6), 401–4. PMID 7091125