Niacin Warnings and Precautions
Prior to using niacin, warnings and precautions for the vitamin should be reviewed with your healthcare provider or pharmacist. For example, it is important to know that niacin should be started at a low dose and increased gradually (in order to avoid intolerable flushing). Since niacin can worsen certain medical conditions, tell your healthcare provider about all other conditions you have before taking niacin products.
You should talk with your healthcare provider prior to taking niacin (brand names include Niacor®, Niaspan®, Slo-Niacin®, and several others) if you have:
- Liver disease, such as cirrhosis, liver failure, or hepatitis
- An ulcer, indigestion, or heartburn
- Chest pain (angina) or other forms of coronary artery disease
- Kidney disease, such as kidney failure (renal failure)
- Low blood pressure (hypotension)
- Any allergies, including allergies to foods, dyes, or preservatives.
Also, let your healthcare provider know if you are:
- Pregnant or thinking of becoming pregnant
Make sure to tell your healthcare provider about any other medications you are taking, including prescription and non-prescription medicines, vitamins, and herbal supplements.
Warnings and precautions to be aware of prior to taking niacin include the following:
- The liver and kidneys help clear niacin from the body. As a result, niacin may not be safe for people with liver or kidney problems. Additionally, niacin can cause or worsen liver damage. For all people taking high doses of niacin (such as the niacin dosage used for improving cholesterol), your healthcare provider should check your liver function (using a simple blood test) periodically, to check for liver damage.
- Different types of niacin are not equivalent. Some may work better than others, and some may be safer. Do not switch between niacin products without your healthcare provider's approval. When switching between different types of niacin, it is recommended to start back with a low dose and gradually increase the dosage, just as if you had never taken niacin before.
- If you have chest pain or any other form of coronary artery disease, check with your healthcare provide before taking niacin. Serious side effects could occur.
- Niacin can increase blood sugar in people with diabetes. If you have diabetes, check with your healthcare provider before taking niacin.
- Niacin can increase the level of uric acid in the blood, which can worsen (and possibly even cause) gout.
- Niacin must be started at a low dose and increased gradually, in order to avoid intolerable flushing (see Niacin Dosage and Niacin Flush for more information).
- Niacin can potentially interact with several other medications (see Niacin Drug Interactions).
- Niacin is considered a pregnancy Category C medication. This means that it may not be safe for use during pregnancy, although the full risks are not known (see Niacin and Pregnancy).
- Niacin passes through breast milk. Therefore, if you are breastfeeding or plan to start, discuss this with your healthcare provider prior to taking the drug (see Niacin and Breastfeeding).