A study of the possible interactions between human platelets and the antibiotic MDL-507 (teicoplanin).

Teicoplanin, a new glycopeptide antibiotic, was tested for its ability to induce agglutination and/or aggregation of fresh and fixed human platelets in vitro. Two chemically related substances, ristocetin and vancomycin, were used as controls in the same experimental conditions, as they are known to be active and, respectively, nonactive on platelets. The studies with fresh platelet rich plasma (PRP) taken from 10 healthy volunteers and the studies with fixed washed platelets (FWP) were carried out at the final concentrations of teicoplanin and vancomycin of 10, 100, 2000 and 5000 mg/l. Unlike ristocetin, teicoplanin did not exhibit any agglutinating or aggregating activity, even when tested for concentrations 50 times as high as those measured in vivo during the peak time. At high concentrations it induced protein precipitation, albeit to a lesser extent than vancomycin.