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November 28, 1980

Dosage of Aspirin-Reply

Author Affiliations

Aspirin Myocardial Infarction Study Rush-Presbyterian-St Luke's Medical Center Chicago

JAMA. 1980;244(21):2414. doi:10.1001/jama.1980.03310210016010

In Reply.—  Dr Wood is correct in stating that at the time AMIS was planned the role of endothelial prostacyclin was unknown. There was, however, ample justification in the selection of the dosage of aspirin used (0.5 g twice daily) from numerous previous field studies that had also used this dosage and reported favorable, if statistically nonsignificant, trends for aspirin.The studies of Masotti and coworkers1 are based on only nine human subjects, three of whom showed sustained inhibition of prostacyclin formation when pretreated with 8 and 10 mg/kg. Under these circumstances it is not possible to state that the dosage of aspirin used in AMIS was likely to inhibit prostacyclin production for a 24-hour period in all subjects. Furthermore, the role of prostacyclin in man has not yet been conclusively established. There is, therefore, no a priori basis for considering the dosage of aspirin used to have been