Clopidogrel dosage

Kimmelstiel C, Badar J, Covic L, et al. Pharmacodynamics and pharmacokinetics of the platelet GPIIb/llla inhibitor tirofiban in patients undergoing percutaneous coronary intervention implications for adjustment of tirofiban and clopidogrel dosage. Thromb Res 2005 I 16( I ) 55-66. 

Quantitative and/or qualitative XRPD methods have been reported to determine the polymorphic content of clopidogrel bisulfate samples, and these have been summarized in Table 2.3. Koradia et al. [16] reported the qualitative analysis of clopidogrel bisulfate in both active pharmaceutical ingredients and tablet dosage forms. Based on the interplanar distances (d-spacing) associated with each polymorph, it was concluded that the molecular packing in Form-I was more dense than that of Form-II, indicating that Form-II would be less stable relative to Form-I. This result was similar with that reported by Bousquet [9]. 

Kamble and Venkatachalam [23] reported a gas chromatography (GC) method for the determination of clopidogrel in tablet dosage forms. This method used a DB-17 capillary column of 30 m length and 0.25 mm internal diameter, equilibrated at an oven temperature of maintained at 250 °C. Dioctyl phthalate was used as an internal standard, and clopidogrel was detected at 4.1 min by means of a flame ionization detector. Linearity in the method ranged from 0.5 to 5.0 mg/ml, with a recovery of 99.89%. 

TABLE 2.5 Summary of HPLC methods used to analyze clopidogrel bisulfate in bulk drug substance and pharmaceutical dosage forms... 

There is no clear evidence that any particular dose of aspirin is more effective than others. However, the symptoms of aspirin toxicity, such as dyspepsia and constipation, are dose related, so the smallest effective dose should be used. A starting dosage of 150-300 mg per day is advised for the acute phase of ischemic stroke followed by longterm treatment with 75-150 mg per day. Patients intolerant of aspirin should be treated with clopidogrel if available, or if not with dipyridamole. These newer agents cost significantly more than aspirin. The use of combination antiplatelet therapy is discussed further in Ch. 24. 

In a placebo-controlled study in 12 healthy subjects, the dosage of heparin given over 4 days did not need modification when clopidogrel 75 mg daily was also given, and the inhibitory effects of clopidogrel on platelet aggregation were unchanged on eoncurrent use. ... 

Clopidogrel and ticlopidine appear to inhibit the metabolism of bupropion. Dosage adjustments may be necessary. 

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