Before taking niacin,
tell your doctor and pharmacist if you are allergic to niacin, any other medications, or any of the ingredients in niacin tablets. Ask your pharmacist or check the manufacturer's information for the patient for a list of the ingredients.
tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: anticoagulants ('blood thinners') such as warfarin (Coumadin); aspirin; insulin or oral medications for diabetes; medications for high blood pressure; nutritional supplements or other products containing niacin; or other medications for lowering cholesterol or triglycerides. If you take insulin or oral diabetes medication, your dose may need to be changed because niacin may increase the amount of sugar in your blood and urine.
if you are taking a bile acid-binding resin such as colestipol (Colestid) or cholestyramine (Questran), take it at least 4 to 6 hours before or 4 to 6 hours after niacin.
tell your doctor if you drink large amounts of alcohol and if you have or have ever had diabetes; gout; ulcers; allergies; jaundice (yellowing of the skin or eyes); bleeding problems; or gallbladder, heart, kidney, or liver disease.
tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking niacin, stop taking niacin and call your doctor.
if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking niacin.
ask your doctor about the safe use of alcoholic beverages while you are taking niacin. Alcohol can make the side effects from niacin worse.
you should know that niacin causes flushing (redness, warmth, itching, tingling) of the face, neck, chest, or back. This side effect usually goes away after taking the medicine for several weeks. Avoid drinking alcohol or hot drinks or eating spicy foods around the time you take niacin. Taking aspirin or another nonsteroidal anti-inflammatory drug such as ibuprofen (Advil, Motrin) or naproxen (Aleve, Naprosyn) 30 minutes before niacin may reduce the flushing. If you take extended-release niacin at bedtime, the flushing will probably happen while you are asleep. If you wake up and feel flushed, get up slowly, especially if you feel dizzy or faint.