Medicines & Supplements A to Z > Niacin


Last updated on 19/03/2021.

Overview   |   Dosage   |    Side Effects   |   Precautions  |   Tips  |   Where To Buy  

GENERIC NAME: Vitamin B3 / Nicotinic Acid / Niacin  



DRUG CLASS: Vitamin (water soluble); Cholesterol lowering drug

USED FOR: Dyslipidemia, high cholesterol levels

OTHER DRUGS IN THE SAME CLASS: Cholestyramine, Ezetimibe, Gemfibrozil, Atorvastatin, Rosuvastatin, Simvastatin

AVAILABLE DOSAGE FORMS: 500mg (capsules)

What is Niacin for?

Niacin is a water-soluble vitamin that has an important role in metabolism, and functioning of the nervous and digestive system. It can also inhibit the breakdown of fats and hinder the formation of fatty acids and therefore can be used as an add-on therapy for hyperlipidemia (high cholesterol), including both hypercholesterolemia and hypertriglyceridemia. Niacin is used to treat niacin deficiency (pellagra) which may be caused by malnutrition, certain medical conditions and medicines.

How to use it?

Niacin can be taken by mouth as extended-release tablets (Niaspan). Do not crush or chew the tablets. You should start with 500 mg once daily at bedtime and your doctor may increase 500 mg every 4 weeks according to your response. The maintenance dose is 1000-2000 mg once daily with a maximum daily dose of 2000 mg.

When used as a dietary supplement, usual adult doses of Niacin range from 50 to 100 mg per day.

What are the side effects of Niacin?

Common side effects of Niacin are head and neck flushing, increase in blood sugar levels, constipation, indigestion, nausea and vomiting.

Who should not take Niacin?

People with
– hypersensitivity to Niacin
– active liver diseases
– active peptic ulcer diseases

Pharmacist Tips:

– Niacin may cause facial flush, and some gastrointestinal discomfort, notify your healthcare provider if this occurs.
– Avoid consumption of alcohol when using this medication.
– Take Niacin at bedtime with a low-fat snack to minimise side effects.

Common dosing schedule:
You should take Niacin with meals.
Avoid hot or spicy foods or liquids when or around the time taking Niacin.

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Niacin may interact with:
– Antidiabetic agents, e.g. Metformin
– Bile acid sequestrants, e.g. Cholestyramine
– Statins, e.g. Simvastatin, Rosuvastatin

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Niacin in Hong Kong?

In Hong Kong, many types of Niacin products are over-the-counter medicine which can be purchased without a prescription from any retail outlet in Hong Kong. This includes grocery stores, convenience stores, medicine shops, and pharmacies. It can also be obtained from doctors.

Niaspan is a prescription-only medicine so it requires a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health. 

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at

Need more information?

For detailed information about the use of Niacin in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.