Which of the following drug causes does not causes thrombocytopenia: March 2009

Ans. B: Aspirin Thrombocytopenia-inducing medications include Direct myelosu ppressi on - Valproic acid Methotrexate - Carboplatin - Interferon Isotretinoin - H2 blockers and Proton-pump inhibitors have shown increased Thrombocytopenia symptoms, such as red dots near the bottom of the legs. -- Ticlopidine Immunological platelet destruction - Datg binds Fab poion of an antibody. The classic example of this mechanism is the quinidine group of drugs. The Fc poion of the antibody molecule is not involved in the binding process. - Drug binds to Fc, and drug-antibody complex binds and activates platelets. Heparin induced thrombocytopenia (HIT) is the classic example of this phenomenon. In HIT, the heparin-antibody-platelet factor 4 (PF4) complex binds to Fc receptors on the surface of the platelet. Since Fc poion of the antibody is bound to the platelets, they are not available to the Fc receptors of the reticulo-endothelial cells, so therefore this system cannot destroy platelets as usual. This may explain why severe thrombocytopenia is not a common feature of HIT. -- Abciximab induced thrombocytopenia. Aspirin inhibits the release of ADP from platelets and their sticking to each other. However, it has no effect on platelet survival time and their adhesion to the damaged vessel wall.