In vitro investigation on the antiaggregating activity of ditazole

The antiaggregating activity of ditazole, a non-steroidal antiinflammatory drug, was assayed in vitro on platelets from 16 subjects at high risk of thrombosis and from 14 healthy control subjects. This study was performed by the photometric method (Born) on platelet rich plasma (PRP), preincubated with ditazole at final concentrations of 1, 2.5, 4 and 40 micrograms/ml. Aggregation was induced by 1 and 2 microM ADP, 1 and 10 microM adrenaline and by 1 and 2 mM arachidonic acid (AA). Ditazole (1 microgram/ml) inhibited platelet aggregation induced by ADP (1 and 2 microM) in both groups and significantly reduced at all concentrations tested adrenaline (10 microM) induced aggregation in subjects at risk, but only at 2.5 micrograms/ml concentration in control subjects. Arachidonic acid (1 mM)-induced aggregation was significantly reduced by ditazole at all concentrations tested in control subjects but only at 2.5 micrograms/ml or more in subjects at risk. In both groups, however, aggregation induced by 2 mM AA was significantly reduced by ditazole at all concentrations tested.