The Action of Aspirin in Preventing the Niacin Flush and its Relevance to the Antischizophrenic Action of Megadose Niacin

Aspirin has been observed to block or attenuate the flush reaction caused by niacin in 90 percent of a group of schizophrenic and nonschizophrenic outpatients. The patients were not treated with tranquilizers or antiinflammatory agents concurrently. The basis for this phenomenon, the blocking of the niacin flush by aspirin, is probably due to inhibition of prostaglandin synthesis by aspirin. In addition inhibition of bradykinin by aspirin may also suppress the flush. The various components of the inflammatory system are briefly described, and their relationship to the flush response is discussed. It is speculated that continued megadose niacin therapy leads to depletion of bradykinin and histamine and a small increase in prostaglandins, particularly of the E type. These are known to exert an inhibitory