Ticlopidine

Pharmaceuticals -> Listed in ZINC15

Pharmaceuticals

2.9

3.46

Freely soluble

2.19e-02 g/L

1 [ug/mL] (The mean of the results at pH 7.4)

156.8 Ų [M+H]+ [CCS Type: DT; Buffer gas: N2; Ionization: ESI+; Dataset: TOXCAST; Source Identifier: DTXSID80202141]

153.84 Ų [M+H]+ [CCS Type: TW; Method: calibrated with polyalanine and drug standards]

Ticlopidine has been associated with serum enzyme elevations in approximately 4% of patients during therapy. These elevations are usually mild, asymptomatic and rarely require dose modification or stopping. Ticlopidine has also been associated with clinically apparent, acute liver injury. While these reactions are rare, more than 50 instances have been reported in the literature and some have been severe. The onset of symptoms is typically within 6 weeks (range 1 to 24 weeks) and marked by onset with fatigue, jaundice and itching. The usual pattern of liver enzyme elevations is cholestatic (~75%), but cases with mixed or hepatocellular enzyme elevations have also been described. Immunoallergic features such as fever, rash and eosinophilia can occur but are not common and, if present, are usually mild. Autoantibody formation is rare. Liver biopsy usually shows cholestatic hepatitis with mixed cellular infiltrates. Most cases are self-limited with recovery within 1 to 3 months, but isolated cases of prolonged jaundice or liver test abnormalities have been described, including at least one case of probable vanishing bile duct syndrome that eventually required liver transplantation. Ticlopidine therapy has also been associated with aplastic anemia and thrombotic thrombocytopenic purpura (TTP) that can be severe and lead to death; these patients may also have accompanying cholestatic liver injury.

Benchmark Dataset for the Liver Toxicity Knowledge Base (LTKB)

ticlopidine

Ticlid

Antithrombotics

4

most-DILI-concern

B01AC05

B - Blood and blood forming organs

QB - Blood and blood forming organs

Binds reversibly (98%) to plasma proteins, mainly to serum albumin and lipoproteins. The binding to albumin and lipoproteins is nonsaturable over a wide concentration range. Ticlopidine also binds to alpha-1 acid glycoprotein (about 15% or less).

Ticlopidine is a prodrug that is metabolised to an as yet undetermined metabolite that acts as a platelet aggregation inhibitor. Inhibition of platelet aggregation causes a prolongation of bleeding time. In its prodrug form, ticlopidine has no significant in vitro activity at the concentrations attained in vivo.

The active metabolite of ticlopidine prevents binding of adenosine diphosphate (ADP) to its platelet receptor, impairing the ADP-mediated activation of the glycoprotein GPIIb/IIIa complex. It is proposed that the inhibition involves a defect in the mobilization from the storage sites of the platelet granules to the outer membrane. No direct interference occurs with the GPIIb/IIIa receptor. As the glycoprotein GPIIb/IIIa complex is the major receptor for fibrinogen, its impaired activation prevents fibrinogen binding to platelets and inhibits platelet aggregation. By blocking the amplification of platelet activation by released ADP, platelet aggregation induced by agonists other than ADP is also inhibited by the active metabolite of ticlopidine.

Half-life following a single 250-mg dose is approximately 7.9 hours in subjects 20 to 43 years of age and 12.6 hours in subjects 65 to 76 years of age. With repeated dosing (250 mg twice a day), half-life is about 4 days in subjects 20 to 43 years of age and about 5 days in subjects 65 to 76 years of age.

Ticlopidine is metabolized extensively by the liver with only trace amounts of intact drug detected. At least 20 metabolites have been identified.