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Niacin
Niacin (brand names include Niacor ®, Niaspan®, Slo-Niacin ®, and several others) is another name for vitamin B 3. Some niacin products are non-prescription supplements, while others are prescription medications.
The term "niacin" can have several different meanings. In the strictest sense, niacin refers to just one compound -- nicotinic acid. However, it can also be used generally to describe other related compounds, including nicotinamide (niacinamide) and inositol nicotinate (inositol hexaniacinate). These types of niacin are not interchangeable and may have different medicinal activities. For the purposes of this article, the term "niacin" will mean nicotinic acid (not the other forms), unless otherwise stated.
Niacin is most often used for high cholesterol, although it may provide other benefits as well.
Niacor and Slo-Niacin are both made by Upsher-Smith Laboratories, Inc. Niaspan is made by Abbott Laboratories. Generic niacin products are made by various manufacturers.
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.
Prescription vs. OTC Niacin
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).
When and How to Take the Drug
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.
The dose that your healthcare provider recommends will vary, depending on a number of factors, including:
- The particular niacin product
- How you respond to the drug
- Other medications you are taking
- Other medical conditions you may have.
As is always the case, do not adjust your dose unless your healthcare provider specifically instructs you to do so.
As with any medicine, niacin can cause side effects. The usefulness of niacin is usually limited by its bothersome (and sometimes dangerous) side effects. Many people stop taking the drug due to intolerable side effects. However, steps can be taken to minimize the side effects and to help you stay on niacin (and to reach a dose that is high enough to be effective).
Common side effects of niacin include, but are not limited to:
(Click Niacin Side Effects to learn more, including potentially serious side effects that you should report immediately to your healthcare provider.)
Drug Interactions With Niacin
What Should I Tell My Healthcare Provider Before Starting Treatment?
You should talk with your healthcare provider prior to taking the medicine if you have:
Also, let your healthcare provider know if you are:
Make sure to tell your healthcare provider about any other medications you are taking, including prescription and non-prescription medicines, vitamins, and herbal supplements.
What If I Take an Overdose?
It is not known what precisely to expect from a niacin overdose. Of course, any of the usual niacin side effects may occur, perhaps more severely. There is one report of dangerously low blood pressure (hypotension) due to a massive niacin dose.
If you happen to overdose, seek immediate medical attention.
This medication should be stored at room temperature, away from moisture and heat. Keep this and all other medications out of the reach of children.
What Should I Do If I Miss My Niacin Dose?
For immediate-release niacin, if you forget to take a dose, take your missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not take a double dose. For slow-release or extended-release niacin products (which are taken just once a day, usually at bedtime), it is probably best to simply skip a missed dose.
If you miss several niacin doses, you will probably need to restart back at a low dose and slowly work up to your previous dosage (just like when starting the medication for the first time), in order to avoid intolerable side effects.
Niacin is available in the following strengths and forms:
- Prescription-only, FDA-approved products:
- Niaspan -- 500 mg, 750 mg, and 1000 mg extended-release tablets
- Niacor -- 500 mg immediate-release tablets
- Immediate release niacin -- numerous strengths, ranging from 100 mg to 500 mg tablets
- Slow-Niacin -- 250 mg, 500 mg, and 750 mg controlled-release tablets
- Various other controlled-release tablets and capsules (labeled as "controlled-release", "timed-release", or "sustained-release" -- numerous strengths, up to 1000 mg in both capsules and tablets.
Different forms of niacin are not interchangeable.
Some (but not all) niacin products are available in generic form (see Generic Niacin).
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List of references (click here)
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Jellin JM, editor. Pharmacist's Letter/Prescriber's Letter Natural Medicines Comprehensive Database Web site. Available at: http://naturaldatabase.com/. Accessed August 31, 2008. Niacor [package insert]. Minneapolis, MN: Upsher-Smith Laboratories, Inc.;2000 February. Niaspan [package insert]. North Chicago, IL: Abbott Laboratories;2008 March. Slo-Niacin [patient package insert]. Minneapolis, MN: Upsher-Smith Laboratories, Inc.;2003 September. Food and Drug Administration, Center for Drug Evaluation and Research. Electronic orange book: approved drug products with therapeutic equivalence evaluations. FDA Web site. Available at: http://www.fda.gov/cder/ob/. Accessed September 1, 2008. Briggs GG, Freeman RK, Yaffe SJ. Drugs in Pregnancy and Lactation. 7th ed. Philadelphia (PA): Lippincott Williams & Wilkins;2005. Mularski RA, Grazer RE, Santoni L, Strother JS, Bizovi KE. Treatment advice on the internet leads to a life-threatening adverse reaction: hypotension associated with niacin overdose. Clin Toxicol (Phila) 2006;44(1):81-4. Centers for Disease Control and Prevention (CDC). Use of niacin in attempts to defeat urine drug testing--five states, January-September 2006. MMWR Morb Mortal Wkly Rep 2007;56(15):365-6. Pieper JA. Understanding niacin formulations. Am J Manag Care 2002;8(12 Suppl):S308-14. Bradberry, JC. Niacin: a new look at an old drug. US Pharm 2003:28:03.
Written by/reviewed by: Kristi Monson, PharmD; Arthur Schoenstadt, MD
Last reviewed by: Kristi Monson, PharmD;
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