"March 11, 2010 - The FDA has put a new "black box" warning on the anti-clotting drug Plavix, the second best-selling drug in the world.
The new label warns that normal doses of Plavix have a potentially deadly lack of effect in 2% "...
(clopidogrel bisulfate) Tablets
DIMINISHED EFFECTIVENESS IN POOR METABOLIZERS
The effectiveness of Plavix is dependent on its activation to an active metabolite by the cytochrome P450 (CYP) system, principally CYP2C19 [see WARNINGS AND PRECAUTIONS]. Plavix at recommended doses forms less of that metabolite and has a smaller effect on platelet function in patients who are CYP2C19 poor metabolizers. Poor metabolizers with acute coronary syndrome or undergoing percutaneous coronary intervention treated with Plavix at recommended doses exhibit higher cardiovascular event rates than do patients with normal CYP2C19 function. Tests are available to identify a patient's CYP2C19 genotype; these tests can be used as an aid in determining therapeutic strategy [see CLINICAL PHARMACOLOGY]. Consider alternative treatment or treatment strategies in patients identified as CYP2C19 poor metabolizers [see DOSAGE AND ADMINISTRATION].
Plavix (clopidogrel bisulfate) is a thienopyridine class inhibitor of P2Y12 ADP platelet receptors. Chemically it is methyl (+)-(S)-α-(2-chlorophenyl)-6,7-dihydrothieno[3,2-c]pyridine-5(4H)acetate sulfate (1:1). The empirical formula of clopidogrel bisulfate is C16H16ClNO2S•H2SO4 and its molecular weight is 419.9.
The structural formula is as follows:
Clopidogrel bisulfate is a white to off-white powder. It is practically insoluble in water at neutral pH but freely soluble at pH 1. It also dissolves freely in methanol, dissolves sparingly in methylene chloride, and is practically insoluble in ethyl ether. It has a specific optical rotation of about +56°.
Plavix for oral administration is provided as either pink, round, biconvex, debossed, film-coated tablets containing 97.875 mg of clopidogrel bisulfate which is the molar equivalent of 75 mg of clopidogrel base or pink, oblong, debossed film-coated tablets containing 391.5 mg of clopidogrel bisulfate which is the molar equivalent of 300 mg of clopidogrel base.
Each tablet contains hydrogenated castor oil, hydroxypropylcellulose, mannitol, microcrystalline cellulose and polyethylene glycol 6000 as inactive ingredients. The pink film coating contains ferric oxide, hypromellose 2910, lactose monohydrate, titanium dioxide and triacetin. The tablets are polished with Carnauba wax.
What are the possible side effects of clopidogrel (Plavix)?
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Stop using clopidogrel and call your doctor at once if you have any of these serious side effects:
- nosebleed or other bleeding that will not stop;
- bloody or tarry stools, blood in your urine;
- coughing up blood or vomit that looks like coffee grounds;
- chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, general ill feeling;
- sudden numbness or...
Prescribing Document Revised: December 2013This monograph has been modified to include the generic and brand name in many instances.
Additional Plavix Information
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