Niacinamide is generally well tolerated in usual doses. Upset stomach, nausea, and diarrhea may occur. If any of these effects last or get worse, notify your doctor or pharmacist promptly.
If your doctor has directed you to use this medication, remember that your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor right away if you have any serious side effects, including: nausea/vomiting that doesn't stop, black/tarry stools, easy bruising/bleeding, swelling of arms/legs, signs of kidney problems (such as change in the amount of urine), dark urine, vomit that looks like coffee grounds, yellowing eyes/skin.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US – Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.
In Canada – Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Niacinamide (nicotinamide) is a form of vitamin B3 (niacin) and is used to prevent and treat niacin deficiency (pellagra). Niacin deficiency can cause diarrhea, confusion (dementia), tongue redness/swelling, and peeling red skin. Niacinamide is often used instead of niacin because it causes fewer side effects (such as flushing). Unlike niacin, niacinamide does not help correct blood fat levels and cannot be substituted for niacin if you are being treated for a blood fat problem (such as high cholesterol).Niacin deficiency may happen as a result of poor diet, certain medical conditions (such as alcohol abuse, malabsorption syndrome, Hartnup disease), or long-term use of certain medications (such as isoniazid). It is best to get your vitamins from healthy foods. A multivitamin may be recommended by your doctor instead of niacinamide because poor diet usually causes deficiencies in more than one vitamin. Vitamins help to support the body's ability to make and break down natural substances (metabolism) and are needed for good health.
How to use Niacin
Take this product by mouth as directed, usually once or twice daily. Follow all directions on the product package, or use as directed by your doctor. If you have any questions, ask your doctor or pharmacist.
Do not crush or chew extended-release tablets. Doing so can release all of the drug at once, increasing the risk of side effects. Also, do not split the tablets unless they have a score line and your doctor or pharmacist tells you to do so. Swallow the whole or split tablet without crushing or chewing.
If you take certain drugs to lower blood fats (bile acid-binding resins such as cholestyramine or colestipol), take niacinamide at least 4 to 6 hours before or after taking these medications. These products may bind with niacinamide, preventing its full absorption.
If your condition lasts or gets worse, or if you think you may have a serious medical problem, get medical help right away.
Before taking niacinamide, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
If you have any of the following health problems, consult your doctor or pharmacist before using this product: liver disease, stomach/ulcer problems, bleeding problems (low platelets), diabetes, gout, kidney disease.
If you have diabetes, this drug may increase your blood sugar. Check your blood sugar regularly as directed and share the results with your doctor. Tell your doctor right away if you have symptoms of high blood sugar such as increased thirst/urination. Your doctor may need to adjust your diabetes medication, exercise program, or diet.
Tell your doctor if you are pregnant before using this medication.
This drug passes into breast milk. Consult your doctor before breast-feeding.
If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.
Lab tests (such as blood sugar, liver function) may be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.
Remember that it is best to get your vitamins and minerals from healthy foods. Maintain a well-balanced diet, and follow any dietary guidelines as directed by your doctor. B vitamins (including niacin) are found in meat, fish, poultry, enriched/whole grain bread products, and fortified cereals. Eat more of these foods to increase the amount of niacin in your diet if you have a niacin deficiency.
If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.
Refer to storage information printed on the package. If you have any questions about storage, ask your pharmacist. Keep all medications away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
Check all prescription and nonprescription medicine labels carefully since vitamins/dietary supplements may also contain niacin or niacinamide (nicotinamide). These may increase your risk of side effects if taken together. Ask your doctor or pharmacist for more details.