Activity ratio between antiprostacyclin and antiaggregating effects of acetylsalicylic acid, indometacin and ditazole.

The effects of acetylsalicylic acid (ASA) indometacin and ditazole on prostacyclin production from rabbit aortic rings were studied in comparison to their inhibiting activity on platelet aggregation. The result were expressed as the ratio between the drug dose inhibiting by 50% prostacycline production and the minimum oral antiaggregating dose. The following ratios were found: 2.4 for ASA, 7.3 for indometacin and 20.4 for ditazole.