Niacin (nicotinic acid) is one of the oldest cholesterol-lowering drugs. A member of the B vitamin family, it’s found in fruits, vegetables, meats, and grains, as well as in most multivitamins. At doses up to 35 milligrams per day, niacin is considered a supplement, but if you’re taking it at doses high enough to lower your cholesterol — more than 100 times the recommended daily intake of 16 milligrams for men and 14 milligrams for women — you need to be taking it under the supervision of your doctor (even though it’s sold over the counter).
Niacin works by reducing the production and release of LDL from the liver, lowering LDL 15 to 20 percent. It also reduces the release of free fatty acids stored in fat cells, which eventually become triglycerides. Thus, it’s an excellent drug for lowering triglycerides, resulting in decreases of 20 to 50 percent. It also raises HDL between 15 and 35 percent. In fact, the branded timed-release form, Niaspan, is one of only two drugs approved to increase HDL. (In case you’re wondering, the other is the fibrate gemfibrozil, brand name Lopid.)
Sound too good to be true? Well, there is a drawback to niacin that turns some people off: It can cause flushing and redness — an intense blush. This occurs because niacin relaxes blood vessels, enabling more blood flow. The blushing usually disappears within an hour or so after taking the drug. And taking aspirin beforehand can reduce this effect, as can gradually building up to the dose you need.
There are two types of nicotinic acid: immediate release and timed release. The timed-release version reduces the flushing, but be doubly sure you don’t take this form without your doctor’s supervision. If you take too much, the drug could cause liver damage and raise blood glucose levels dangerously high. It can also raise blood glucose and hemoglobin AIC levels in people with diabetes. That’s why most experts recommend starting with the immediate-release form. Also, make sure you’re taking nicotinic acid; another form of niacin called nicotinamide doesn’t lower cholesterol levels.
Side effects: In addition to flushing, other possible side effects of niacin include:
- Liver enzyme abnormalities. About 5 percent of people who take more than 3 grams of nicotinic acid per day may learn they have elevated liver enzymes, an indication that their liver is under stress. If the elevation continues and your enzymes are more than three times normal levels, your doctor may want you to stop taking the drug.
- Blood glucose control. In about 10 percent of people — particularly those with diabetes, insulin resistance, or metabolic syndrome — nicotinic acid may make it more difficult to control blood sugar levels.
- Gout. About 5 to 10 percent of those people taking nicotinic acid find their production of uric acid increases. This can result in gout, a condition involving painful and inflamed joints.
- Gastrointestinal symptoms. Infrequently a variety of gastrointestinal symptoms, including nausea, indigestion, gas, vomiting, diarrhea, and ulcers, may also occur.
- Muscle toxicity. This is rare but may occur if you’re combining nicotinic acid with other drugs, such as statins or fibrates.
Warnings: Don’t take niacin if you have diabetes, liver disease, an active peptic ulcer, arterial bleeding, or unexplained liver enzyme elevations. And be careful if you’re also taking blood pressure medication. Niacin can increase the effect of some blood pressure drugs, so your doctor should closely monitor your blood pressure when you first start taking niacin.
Recommended dose: 1 to 3 grams daily, taken under a doctor’s supervision.