Oral Administration of Sustained Release Niacin Inhibits Platelet Aggregation.

Abstract

Previous studies have suggested that niacin may have antiplatelet properties, however the effects of niacin on the platelet activity are not well defined. The purpose of this trial was to investigate whether the oral administration of niacin inhibits platelet aggregation. This study was run in three segments measuring the inhibitory effect of niacin: 1) 3 mmol/L niacin in vitro, 2) one hour after 1-gram sustained-release (SR) niacin administration, 3) twelve hours after 2-gram SR niacin administration. Platelet aggregation was measured using the VerifyNow-Aspirin and whole blood impedance aggregometry. Preincubation with niacin resulted in a significant inhibition of platelet aggregation. Significant inhibition of platelet aggregation was found one hour following the oral administration of 1 gram of SR niacin while the oral administration of a 2 gram dose of SR niacin did not produce significant platelet inhibition when platelet aggregation was measured 12 hours after the dose. Niacin has a small, direct effect on platelet aggregation. Niacin platelet inhibition is transient and may dissipate as it is converted into metabolites. The clinical significance is unknown.