TICLOPIDINE HYDROCHLORIDE

Clinical safety rating: safe

Animal studies have demonstrated safety

How it works

Ticlopidine is a thienopyridine inhibitor of platelet aggregation. It irreversibly inhibits the P2Y12 receptor on platelets, blocking ADP-mediated platelet activation and aggregation.

What the body does with it

Metabolism	Ticlopidine is extensively metabolized in the liver, primarily by CYP2C19 and CYP3A4, with minor contributions from CYP1A2 and CYP2B6.
Excretion	Primarily hepatic metabolism; renal excretion of metabolites accounts for approximately 60% of the dose, with 23% excreted in feces as metabolites. Less than 2% of the dose is excreted unchanged in urine.
Half-life	The terminal elimination half-life is approximately 24-36 hours after single-dose administration, prolonging to 4-5 days after multiple dosing due to time-dependent pharmacokinetics. This necessitates a loading dose regimen (e.g., 250 mg twice daily) to achieve steady-state within 2-3 days.
Protein binding	98% bound to serum proteins, primarily to albumin and lipoproteins.
Volume of Distribution	Volume of distribution is approximately 0.5 L/kg, indicating distribution into total body water and some tissue binding.
Bioavailability	Oral bioavailability is approximately 80-90% after a single dose, but is reduced to 50-60% in the presence of food due to decreased absorption. Administration with meals is recommended to minimize gastrointestinal side effects.
Onset of Action	Oral: Inhibition of platelet aggregation is detectable within 24 hours after a single 250 mg dose, with maximal effect occurring after 3-5 days of continuous dosing. There is no intravenous formulation.
Duration of Action	The antiplatelet effect persists for several days after discontinuation, with platelet function returning to normal within 10-14 days after the last dose. This prolonged effect reflects irreversible inhibition of platelet ADP receptors.

Classification & Brands

Dosing & administration

250 mg orally twice daily

Dosage form	TABLET
Renal impairment	No dose adjustment required for mild to moderate impairment (CrCl >30 mL/min). Insufficient data for severe impairment (CrCl <30 mL/min); use with caution.
Liver impairment	Contraindicated in severe hepatic impairment (Child-Pugh class C). For moderate impairment (Child-Pugh class B), use with caution and monitor liver function; no specific dose recommendation.
Pediatric use	Safety and efficacy not established; no standard pediatric dosing.
Geriatric use	Use with caution due to increased risk of bleeding and neutropenia. No specific dose adjustment, but monitor clinical response and adverse effects closely.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Proton pump inhibitors may reduce its antiplatelet effect Can cause severe neutropenia and thrombotic thrombocytopenic purpura (TTP).

Breastfeeding

Excretion into breast milk is unknown; however, other thienopyridines have low transfer. M/P ratio not available. Caution advised due to potential for bleeding in the infant. Consider risk versus benefit.

Teratogenic Risk

Ticlopidine is classified as FDA Pregnancy Category B. Animal studies have not demonstrated teratogenic effects, but there are no adequate and well-controlled studies in pregnant women. First trimester: limited data; theoretical risk of bleeding due to antiplatelet effect. Second and third trimesters: may increase risk of maternal hemorrhage, placental abruption, and fetal intracranial hemorrhage; avoid near term.

Warnings & precautions

■ FDA Black Box Warning

Ticlopidine can cause life-threatening hematological adverse reactions including neutropenia, agranulocytosis, thrombotic thrombocytopenic purpura (TTP), and aplastic anemia. Neutropenia occurs within the first 3 months of therapy. Frequent monitoring of CBC is required.

Side Effect Profile

Common Effects	Diarrhea
Serious Effects

Absolute Contraindications

History of neutropenia, thrombocytopenia, or hemostatic disorder. Active bleeding (e.g., peptic ulcer, intracranial hemorrhage). Severe hepatic impairment. Hypersensitivity to ticlopidine or any component.

Clinical Precautions

Precautions

Hematotoxicity: neutropenia, agranulocytosis, TTP, aplastic anemia. Bleeding risk: increased due to antiplatelet effect. Hepatic impairment: may increase exposure. Renal impairment: use with caution. Discontinue prior to surgery if antiplatelet effect not desired. Drug interactions: increased levels of theophylline, phenytoin, and warfarin.

Clinical Tips & Counseling

Drug interactions

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