['Niacin is an effective treatment for dyslipidemia due to its favorable effects on multiple lipid parameters. Clinical utility of niacin is sometimes limited, however, because of cutaneous flushing. A once-daily, extended-release (ER) niacin formulation has been shown to significantly reduce flushing compared to immediate-release niacin. An optimized (reformulated) version of niacin ER has recently been developed and was shown in a previous study to significantly reduce flushing intensity (severity) compared to the non-optimized (commercial) formulation. The current study was designed to evaluate the effect of aspirin on various indices of flushing when administered with the optimized niacin ER formulation.', 'This was a randomized, double-blind, double-dummy, placebo-controlled flush provocation crossover study in healthy males. To increase the probability of flushing, subjects received a single dose of reformulated niacin ER 2,000 mg, which is the upper limit of the approved dosage range. Subjects received 650 mg aspirin orally either 30 minutes before or concomitantly with niacin ER, or placebo with niacin ER, in 3-way crossover fashion. The primary endpoint was the number of subjects who reported at least one flushing event. Secondary endpoints included the perceived intensity and duration of flushing symptoms.', 'In the 148 men who completed all treatments, aspirin significantly reduced flushing incidence (the primary endpoint) following administration of niacin ER compared with placebo. Among subjects receiving placebo, 77% of subjects reported flushing with niacin ER. Among subjects receiving aspirin, 53-61% of subjects reported flushing (pretreatment and concomitant treatment, respectively, both p < 0.001 compared with placebo) with niacin ER. Aspirin also significantly reduced intensity and duration of flushing (by 30-40%) compared with no aspirin. The two aspirin-containing treatments (i.e. pre- or concomitant treatment) were similar in their effects on flushing incidence, intensity and duration. Median intensity on a 100 mm visual analogue scale (VAS) was reduced from 33 mm with placebo to 19-23 mm with aspirin. Median duration was reduced from approximately 1 hour with placebo to 37-48 minutes with aspirin.'] Does aspirin reduce cutaneous flushing after administration of an optimized extended-release niacin formulation?