Tablets: 75 mg and 300 mg
FDA Interactions/Dosages:
For the reduction of atherosclerotic events (myocardial infarction, stroke, and vascular death) in patients with atherosclerosis documented by recent stroke, recent myocardial infarction, or established peripheral arterial disease: The recommended dose is 75 mg once daily with or without food.
For the reduction of atherosclerotic events in patients with acute coronary syndrome including unstable angina and non-Q-wave myocardial infarction: Therapy should start with a 300 mg loading dose and then continued at 75 mg once a day. Aspirin (75 mg - 325 mg) should be initiated and continued in combination with clopidogrel. Most patients will also be treated acutely with heparin.
Pharmacology/Pharmacokinetics
Clopidogrel is converted by CYP2C19 to its active metabolite which inhibits platelet aggregation by irreversibly modifying platelet receptors thereby selectively inhibiting the binding of adenosine diphosphate (ADP) to the receptor. This results in an inhiation of the ADP-mediated activation of the glycoprotein GPIIb/IIIa complex and an inhibition of platelet aggregation. Patients who are CYP2C19 poor metabolizers can be identified through genotype testing. Clinical effects are seen 2 hours after an oral dose and a steady state of platelet aggregation occurs after 3 to 7 days. Clopidogrel and its active metabolite are bound to plasma proteins (98% and 94% respectively).
Drug Interactions:
Use may predispose occult blood loss in patients taking NSAIDs. Clopidogrel inhibits CYP2C9 enzyme therefore it may interfere with the metabolism of phenytoin, tamoxifen, tolbutamide, warfarin, torsemide, fluvastatin, and NSAIDs. Omeprazole and esomeprazole may decrease effects.
Contraindications/Precautions:
Contraindicated in active pathological bleeding such as peptic ulcer or intracranial hemorrhage. Use with caution in patients who may be at risk of increased bleeding from trauma, surgery, or other pathological conditions. Use with caution in patients with severe hepatic disease. Rare cases of thrombotic thrombocytopenic purpura (TTP) have been reported in patients taking clopidogrel. Most TTP patients present with initial nonspecific complaints of fatigue, weakness, anorexia, nausea, diarrhea, and abdominal pain. Clopidogrel is excreted in breast milk of studied rats. DO NOT USE IN PATIENTS IDENTIFIED WITH TWO LOSS-OF-FUNCTION ALLELES OF THE CYP2C19 GENES. Pregnancy Category B.
Adverse Effects:
Upper respiratory tract infection (8.7%), chest pain (8.3%), headache (7.6%), flu-like symptoms (7.5%), arthralgia (6.3%), dizziness (6.2%), back pain (5.8%), abdominal pain (5.6%), purpura (5.3%), dyspepsia (5.2%), diarrhea (4.5%), dyspnea (4.5%), rhinitis (4.2%), rash (4.2%), hypertension (4.3%), edema (4.1%), bronchitis, coughing, urinary tract infection, pruritus, depression, nausea, epistaxis, and fatigue (<4%).
Contact your physician if the above side effects are severe or persistent.
Contact your physician if you notice any indication of infection including fever, chill, or sore throat (neutropenia) or signs of TTP including fatigue, weakness, anorexia, nausea, diarrhea, and abdominal pain.
Can be taken without regard to meals.
Bleeding time will be increased during therapy--report unusual bleeding to your physician.
Tell your physician and dentists about your therapy before elective surgery.
Do not exceed prescribed dosage; take medication only as directed.
Do not take over-the-counter omeprazole products wile on clopidogrel.
If a dose is missed, take it as soon as possible. If it is closer to the time of your next dose than the dose you missed, skip the missed dose and return to your dosing schedule. Do not double doses.