Niacin flushing is a common side effect of niacin supplements, which can cause skin flushing, itching, and a burning sensation. Alcohol, on the other hand, is a depressant that can affect the central nervous system and cause various health issues. According to the sources provided, there is no direct evidence that alcohol can exacerbate niacin flushing. However, it is essential to note that alcohol consumption can increase the risk of liver damage, which can affect the body's ability to metabolize niacin and other nutrients.

According to Drug Patent Watch [1], alcohol is not a drug or medication that can cause or exacerbate niacin flushing. Alcohol is a common beverage that is used for recreational purposes and can have various health effects, including liver damage, addiction, and impaired judgment.

Mayo Clinic [2] states that niacin supplements can cause flushing, especially when taken in high doses. The flushing is usually harmless and can be managed by taking the supplement with food or a low dose of aspirin. However, niacin supplements can cause liver damage when taken in high doses, which can be exacerbated by alcohol consumption. Therefore, it is recommended to avoid alcohol when taking niacin supplements.

According to a study published in the Journal of Clinical Lipidology [3], niacin-induced flushing is not affected by alcohol consumption. The study found that alcohol consumption did not significantly affect the incidence or severity of niacin-induced flushing. However, the study also found that alcohol consumption can increase the risk of liver damage, which can affect the body's ability to metabolize niacin and other nutrients.

In conclusion, while there is no direct evidence that alcohol can exacerbate niacin flushing, alcohol consumption can increase the risk of liver damage, which can affect the body's ability to metabolize niacin and other nutrients. Therefore, it is recommended to avoid alcohol when taking niacin supplements to reduce the risk of liver damage.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/ALCOHOL
[2] https://www.mayoclinic.org/drugs-supplements-niacin/art-20364984
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2779993/