Generic Clopidogrel: Has Substitution for Brand Name Plavix® Been Effective?

Area of Science:

• Pharmacology
• Cardiovascular Medicine
• Clinical Pharmacy

Background:

• The patent expiration of Plavix® (clopidogrel bisulfate) led to the approval of generic versions.
• Significant inter-patient variability exists in clopidogrel pharmacokinetics and pharmacodynamics.
• Data on the clinical impact of switching to generic clopidogrel bisulfate is crucial.

Purpose of the Study:

• To compare the efficacy of generic clopidogrel bisulfate versus Plavix® in inhibiting platelet aggregation.
• To assess the impact of generic clopidogrel bisulfate on antiplatelet resistance.
• To evaluate secondary clinical events in patients on both formulations.

Main Methods:

• Retrospective review of patients on Plavix® (n=254) or generic clopidogrel bisulfate (n=185) monotherapy.
• Assessment of confounding factors: diabetes, female sex, smoking, and interacting medications.
• Platelet aggregation measured by whole blood impedance aggregometry using adenosine diphosphate; non-responders defined as >6 ohms impedance.

Main Results:

• Introduction of generic clopidogrel bisulfate correlated with reduced antiplatelet resistance (44% to 31%, p<0.01).
• Mean resistance (ohms) decreased significantly post-switch (5.06 ± 4.55 to 3.32 ± 4.03, p<0.01).
• No statistically significant difference in secondary clinical events was observed.

Conclusions:

• Generic clopidogrel bisulfate formulations are associated with significantly lower resistance rates.
• Further research is warranted to investigate variability between different generic clopidogrel bisulfate formulations.
• The switch to generic clopidogrel bisulfate appears safe and effective for platelet aggregation inhibition.