Niacin works in several ways to improve cholesterol levels. It is thought that it works to increase HDL cholesterol ("good" cholesterol) levels by preventing the liver from removing HDL from the bloodstream. Additionally, niacin seems to decrease the liver's production of LDL and VLDL, two types of "bad" cholesterol. It also helps decrease the release of fatty acids (from body fat) into the bloodstream. It is important to note that nicotinic acid (not niacinamide or nicotinamide) has these effects on cholesterol.
Niacin might also help reduce blood clotting by decreasing the level of fibrinogen in the blood. Fibrinogen is used to make fibrin, an important component of blood clots.
Niacin comes in many different forms (such as immediate-release, slow-release, controlled-release, and extended-release products) and is available both by prescription (Niacor, Niaspan) or over the counter (Slo-Niacin and many others). These products are not interchangeable; some work better than others, and some are safer (see Types of Niacin for more information).
General considerations for when and how to take the medication include the following:
- The medication comes in capsule and tablet form. It is taken by mouth several times a day (for immediate-release products), once or twice daily (for slow-release), or once daily at bedtime (for Niaspan, the prescription-only, extended-release form).
- To help avoid stomach irritation and upset, it is best to take your dosage with a meal or a snack.
- Your healthcare provider may recommend taking aspirin or a nonsteroidal anti-inflammatory drug (NSAID) 30 minutes before each dose to help minimize niacin flush.
- It is a good idea to avoid spicy food, alcohol, or hot beverages after taking a dose of niacin, as these foods and drinks may increase the risk of flushing.
- Do not start out with the full-strength recommended niacin dosage, as you will likely experience intolerable side effects. Instead, you should start with a low dose and increase your dose gradually as your healthcare provider recommends. If you miss a few doses, you should start over with a low dose, in order to minimize side effects.
- For the medication to work properly, it must be taken as prescribed. Even with non-prescription products, you should take high doses of niacin (such as the doses required to improve cholesterol) only with your healthcare provider's approval and supervision, as the drug is a powerful and potentially dangerous medication.