Nicotinic acid or niacin, the water-soluble B vitamin, improves all lipoproteins when given in doses well above the vitamin requirement. Nicotinic acid lowers total cholesterol, LDL-cholesterol, and triglyceride levels, while raising HDL-cholesterol levels. There are three types of nicotinic acid: immediate release, timed release, and extended release. Most experts recommend starting with the immediate-release form; discuss with your doctor which type is best for you. Nicotinic acid is inexpensive and widely accessible to patients without a prescription but must not be used for cholesterol lowering without the monitoring of a physician because of the potential side effects. (Nicotinamide, another form of the vitamin niacin, does not lower cholesterol levels and should not be used in the place of nicotinic acid.) All patients taking nicotinic acid to lower serum cholesterol should be closely monitored by their doctor to avoid complications from this medication. Self-medication with nicotinic acid should definitely be avoided because of the possibility of missing a serious side effect if not under a doctor's care. Patients on nicotinic acid are usually started on low daily doses and gradually increased to an average daily dose of 1.5 to 3 grams per day for the immediate release form, and 1.5 to 2 grams per day for the other forms. Nicotinic acid reduces LDL-cholesterol levels by 10 to 20 percent, reduces triglycerides by 20 to 50 percent, and raises HDL-cholesterol by 15 to 35 percent. A common and troublesome side effect of nicotinic acid is flushing or hot flashes, which are the result of blood vessels opening wide. Most patients develop a tolerance to flushing and, in some patients, it can be decreased by taking the drug during or after meals or by the use of aspirin or other similar medications prescribed by your doctor. The extended release form may cause less flushing than the other forms. The effect of high blood pressure medicines may also be increased while you are on niacin. If you are taking high blood pressure medication, it is important to set up a blood pressure monitoring system while you are getting used to your new niacin regimen. A variety of gastrointestinal symptoms including nausea, indigestion, gas, vomiting, diarrhea, and the activation of peptic ulcers have been seen with the use of nicotinic acid. Three other major adverse effects include liver problems, gout, and high blood sugar. Risk of the latter three increases as the dose of nicotinic acid is increased. Your doctor may possibly not prescribe this medicine for you if you have diabetes, because of the effect on your blood sugar.