Its mechanism of action and of its precursor ticlopidine was still unknown .
Clopidogrel , a second generation thienopyridine , started in preclinical trials in 1987 and reached global market in 1998 .
Clopidogrel 's mechanism of action and of its precursor ticlopidine was still unknown .
Clopidogrel , a second generation thienopyridine , started in preclinical trials in 1987 and reached global market in 1998 .