Platelet reactivity on brand and generic clopidogrel chronic therapy

Abstract

Introduction: Generic drugs are approved when they are shown to be bio-equivalent in their pharmacokinetic profiles. Whether the pharmacological effect of the generic formulation is similar to the brand is not always easy to see if there is no observable physiological effect of the drug. ADP multiplate test is used to measure platelet reactivity in blood samples from patients who are taking P2Y12 inhibitors. The study aims was to compare platelet reactivity using multiplate ADP test while on brand clopidogrel (Plavix) and generic clopidogrel (Pedovex). Methodology: Patients gave informed consent to participate in this prospective open label cross over study. Patients took brand clopidogrel (Plavix) for one month followed by ADP testing then switched to (Pedovex) for one month with repeat APD testing or vice versa. All patients were stable on chronic therapy. Those who had a stent less than one month were not included in the study. All physicians taking care of patients were blinded to the ADP results till the study was completed. Results: 89 patients gave informed consent. Complete ADP data was available for 73 patients. No patient had any stent thrombosis event during the course of the study and none had any bleeding episode. Both formulations were equally well tolerated. Concordant response of ADP was observed in 89% of the patients and was discordant in 11%. ADP response was lower in 4 patients while on brand clopidogrel and was lower in 4 patients while on generic clopidogrel. Conclusion: Generic clopidogrel (Pedovex) was similar to brand clopidogrel (Plavix) in its effect on ADP Multiplate test on Chronic Therapy.