Niacin is a very interesting medication. As most people know, niacin is a "B" vitamin, but to change cholesterol values requires much larger amounts than the body requires as a vitamin. So you need to think of it as a drug, not a vitamin, and actually it often has more side effects than prescription medications such as statins.
Niacin lowers cholesterol and LDL, but it also is the most effective available agent to raise HDL (the "good" cholesterol) and lower triglycerides. (For a discussion of what all of these types of cholesterol are, click here) But niacin can cause side effects, and it is important to know how to take it. Here is what you need to know:
The most common side effects with niacin are flushing and stomach upset. The flushing usually occurs about an hour after a dose, and can be felt as anything from a mildly warm feeling to a sensation of unpleasant heat, like a bad sunburn. It can be accompanied by redness of the skin and occasionally a rash. Tolerance to the flushing builds up very rapidly, and usually the flushing disappears altogether after a few days or weeks. Stomach upset or heartburn occurs less often, and is minimized by taking the medication with food. Nonetheless, we usually avoid niacin in patients who already have reflux symptoms that are not well controlled.
Niacin can also make gout and diabetes worse. It can be used when these disorders are well controlled but not if they are not in good control.
Here is how to use niacin so that side effects are minimized:
Niacin comes in both regular and extended release forms. The regular niacin produces more flushing and has to be taken more often so I generally recommend the extended release form. There are really only two preparations of niacin that I recommend: Niaspan - a prescription form of the medication that has gone through the Food and Drug Administration (FDA) process of approval and that is usually covered by health insurance, and Slo-Niacin - a very high quality over-the-counter preparation made by Upsher-Smith. The reason for recommending a very specific over-the-counter preparation is that dietary supplements are essentially unregulated - you can make niacin capsules at home and sell them in the local health food store as Morning Glory niacin! In fact, there have been some dangerous niacin preparations on the market, at least one of which caused liver function abnormalities because of a toxic coating and not due to the niacin itself. So in self-defense, I recommend the preparation that I know is safe and effective.
One starts with a low dose and works up to the appropriate level. I generally start with 500 mg once a day and increase the dose every few weeks as tolerated. The working range for niacin is between 1000 and 2000 mg daily (1-2 grams). Less than 1000 mg does not produce much of an effect and more than 2000 mg usually just increases side effects with not much more benefit.
Niacin should always be taken with food, never on an empty stomach. Niaspan comes with a recommendation to take it with a snack before going to sleep. I don't like to encourage people to eat before they go to sleep, and so generally recommend that it be taken after dinner.
Patients on niacin should generally be on a full dose aspirin daily (enteric, or “safety” coated) as the flushing symptoms of niacin are to a large extent blocked by aspirin.
Niaspan is a remarkably "unforgiving" drug. Several of my patients have commented that if they miss a single day they will flush the next day, as tolerance will have already worn off. So it is especially important to never miss a dose of this medication. Of course, it is important to take all medications as prescribed, but if you go on a weekend trip, forget to take your medicines with you, and then on Monday take the full 2000 mg that you were used to taking with no problems, you may have a rude surprise!
Niacin over the counter also comes as "flush-free" preparations. Unfortunately these, when tested, have also turned out to have markedly reduced beneficial effects.
But don't let all of the above scare you off. Niacin is really a very good drug, and as I said above it is the best drug for raising HDL and lowering triglycerides, and most people tolerate it just fine. And niacin works very well in combination with statins, which lower LDL more but have a smaller effect on HDH and triglycerides.