Nicotinamide

Indications

Niacin (vitamin B3, also called nicotinic acid) is found mainly in B-complex and multivitamin products, used to prevent and treat niacin deficiency. Severe deficiency causes pellagra, with a rough rash on sun-exposed skin, diarrhoea and confusion. In higher prescription doses, niacin has been used to improve blood cholesterol and triglyceride levels, but only under a doctor's supervision.

How It Works

The body turns niacin into substances that enzymes need to release energy from food and to keep the skin, nerves and digestive system healthy. In high doses it also reduces the liver's production of some blood fats.

Dosage and Administration

Supplements: take as directed on the pack. Adults normally need about 14 to 16 mg a day, which most multivitamins provide. Pellagra and other deficiency: as advised by the doctor. Cholesterol treatment uses much higher doses and must be started and increased only by a doctor. Taking it with food reduces stomach upset and flushing.

Interactions

At high doses: with statins such as Atorvastatin the risk of muscle problems increases; it can add to the effect of blood pressure medicines and cause dizziness; it can raise blood sugar and weaken diabetes medicines; alcohol and hot drinks make flushing worse. Take Colestyramine 4 to 6 hours apart from niacin.

Contraindications

Allergy to niacin. High doses should not be used in active liver disease, an active stomach ulcer, or active bleeding.

Side Effects

At supplement doses side effects are uncommon. Higher doses often cause flushing (warmth, redness and itching of the face and body), stomach upset and headache, and can raise blood sugar and uric acid (gout). Get urgent medical help for yellowing of the skin or eyes, dark urine, muscle pain with weakness or dark urine, fainting, or a serious allergic reaction.

Pregnancy and Lactation

The normal amounts found in pregnancy and general multivitamins are safe. High-dose niacin is not recommended during pregnancy or breastfeeding.

Precautions and Warnings

Do not take high-dose niacin without medical supervision. Use with care if you have diabetes, gout, liver disease, or drink alcohol heavily. Your doctor may check liver tests and blood sugar during high-dose treatment. Do not switch between different niacin products at high doses without advice.

Overdose

Large amounts can cause severe flushing, dizziness, vomiting and low blood pressure. Seek medical help if a large amount has been taken.

Therapeutic Class

Vitamin B3 (water-soluble vitamin); lipid-modifying agent at high doses.

Storage

Store below 30°C in a dry place, away from light and out of the reach of children.