Aspirin blocks nicotinic acid–induced flushing

Abstract

Nicotinic acid flushing after placebo and 975-mg oral doses of aspirin was assessed in 29 normal subjects over a range of nicotinic acid doses. Intensity of flushing was assessed by the change in malar thermal circulation index (.DELTA.MTCI). Aspirin pretreatment resulted in smaller .DELTA.MTCI at the higher doses of nicotinic acid. At the lower doses, the change in the index after pretreatments with both aspirin and placebo remained low, suggesting that very little flushing was provoked by these doses. These results are compatible with the proposed mediation by prostaglandins of the nicotinic acid-induced flush. According to the .DELTA.MTCI method, flushing is quantitatively characterized as a nonquantal, dose-response reaction of variable intensity.