Drug-induced thrombocytopenia is associated with increased binding of IgG to platelets both in vivo and in vitro

Thrombocytopenia is a common serious adverse effect of drug treatment. A variety of in vitro diagnostic techniques to confirm the diagnosis are available, but the majority lack sufficient sensitivity to detect all cases of drug-induced thrombocytopenia. We studied 19 patients with suspected drug-induced thrombocytopenia and demonstrated that platelet- associated IgG (PAIgG) was elevated in all at the time of thrombocytopenia, and PAIgG returned to normal levels as the thrombocytopenia resolved. In the majority of patients, the platelet count rapidly returned to normal after the drug was discontinued; however, in six patients, the thrombocytopenia persisted well beyond the period of time that the offending drug would be expected to be cleared from the blood. In 13 patients, serum obtained after recovery was used to identify the drug responsible for the thrombocytopenia in an in vitro assay. In all cases, the addition of the drug historically associated with the thrombocytopenic episode was associated with an increased binding of IgG to control platelets. For uncertain reasons, the concentration of drug required to increase the in vitro binding of IgG to test platelets was often more than the concentration usually achieved in vivo. Wider application of these techniques may provide better understanding of the clinical characteristics and mechanisms responsible for drug-induce thrombocytopenia.     

吡唑烷酮类化合物的抗惊厥作用

对3类14种吡唑烷酮类化合物的抗惊厥作用进行了比较研究,它们对最大电休克惊厥均有对抗作用,作用出现快,但维持时间较短,其中II-f作用最强,对听源性发作和家兔海马注射硫酸锌形成的慢性癫痫模型也有效。此外,III-类尚能对抗戊四唑引起的阵挛性惊厥。