Niacin vs Nicotinamide — Critical Distinction
| Property | Nicotinic Acid (Niacin) | Nicotinamide (Niacinamide) | Extended-Release Niacin |
|---|
| Flushing | ✅ Yes (prostaglandin-mediated) | ❌ No flushing | ⚡ Reduced (less than IR) |
| Lipid-lowering | ✅ Yes (HDL↑, TG↓, LDL↓) | ❌ No lipid effect | ✅ Yes (similar to IR) |
| Pellagra treatment | ✅ Effective | ✅ Preferred (no flush) | ✅ Effective |
| Hepatotoxicity | Low (at therapeutic doses) | Low | ⚠️ Higher risk (monitor LFTs) |
| India availability | Tablets; injectable | Widely available | Limited brands |
Pellagra — Still Present in India
Pellagra (niacin deficiency) presents with the "4 Ds": Dermatitis (photosensitive, Casal's necklace), Diarrhoea, Dementia, and Death. It remains clinically relevant in India — particularly in jowar/sorghum-eating populations (Telangana, Maharashtra, Karnataka), chronic alcoholics, isoniazid-treated TB patients (isoniazid blocks niacin synthesis from tryptophan), carcinoid syndrome, and Hartnup disease. Nicotinamide is the preferred treatment — does not cause flushing and is equally effective for deficiency.
Niacin for Dyslipidaemia
Niacin (nicotinic acid) is the most effective agent available for raising HDL cholesterol (increases HDL by 15–35%) and reducing triglycerides (by 20–50%). However, use as dyslipidaemia therapy has declined after the AIM-HIGH and HPS2-THRIVE trials showed no cardiovascular outcome benefit when added to statins. It may still be considered when statins are contraindicated or in isolated hypertriglyceridaemia. Start at 100–250 mg/day and titrate slowly. Aspirin 325 mg 30 minutes before dosing reduces flushing.
Minimising Niacin Flush
The niacin flush (warmth, redness, itching) is prostaglandin-mediated and typically subsides within 2–4 weeks of regular use. Strategies to minimise: start low and titrate slowly; take with meals; take aspirin 325 mg 30 minutes before; avoid alcohol and hot drinks around dosing; use extended-release formulations (less flush but higher hepatotoxicity risk); do not take on empty stomach.
Normal Niacin/NAD Levels
Serum niacin levels are not routinely measured. Urinary N1-methylnicotinamide <5.8 mg/day indicates deficiency. Urinary 2-pyridone/N1-methylnicotinamide ratio <1 confirms deficiency. In practice, pellagra is diagnosed clinically.
Frequently Asked Questions
What is the dose of niacin for pellagra?
Nicotinamide 100–300 mg/day in divided doses × 3–4 weeks (adults). Children: 50–100 mg/day in divided doses. Nicotinamide is preferred over nicotinic acid for pellagra as it does not cause flushing. After clinical recovery, dietary supplementation is essential — address underlying cause (alcoholism, maize diet without lime processing, isoniazid therapy).
What is the difference between niacin and nicotinamide?
Niacin (nicotinic acid) causes prostaglandin-mediated flushing and has significant lipid-lowering effects — used for dyslipidaemia. Nicotinamide (niacinamide) causes NO flushing and has NO lipid-lowering effect — used for pellagra, deficiency treatment, and skin conditions. Both are forms of vitamin B3 and both treat deficiency states. For pellagra — use nicotinamide. For lipids — use nicotinic acid (niacin).
Is pellagra still seen in India?
Yes. Pellagra is still diagnosed in India, particularly in jowar/sorghum-eating regions (Telangana, Maharashtra, Karnataka), in chronic alcoholics, patients on isoniazid (TB treatment), carcinoid syndrome, and Hartnup disease. The 4 Ds (Dermatitis, Diarrhoea, Dementia, Death) are the classic presentation. Isoniazid-associated pellagra is the most common drug-induced cause seen in Indian TB patients — treat with pyridoxine (B6) + nicotinamide.
How do I reduce niacin flushing?
Take aspirin 325 mg (or ibuprofen 200 mg) 30 minutes before the niacin dose. Start at a low dose (100–250 mg) and titrate up slowly over weeks. Take with food. Avoid alcohol, hot beverages, and hot showers around the time of dosing. Flush tolerance develops within 2–4 weeks of regular use. Extended-release formulations cause less flushing. Nicotinamide does not cause flushing at all.
What is the niacin dose for high triglycerides?
Nicotinic acid for hypertriglyceridaemia: start 500 mg at bedtime, titrate by 500 mg every 4 weeks to a target of 1500–3000 mg/day (in 2–3 divided doses). Extended-release niacin: start 500 mg at bedtime, titrate to 1000–2000 mg/day. Monitor LFTs, glucose, and uric acid at baseline and every 6–12 weeks. Note: evidence for cardiovascular outcome benefit when added to statins is lacking — use primarily for isolated hypertriglyceridaemia or statin intolerance.
Can niacin cause liver damage?
Hepatotoxicity risk is low with immediate-release (IR) nicotinic acid at standard doses. Extended-release (ER) niacin carries higher hepatotoxicity risk — monitor LFTs at baseline, 3 months, then 6-monthly. Risk factors: alcohol use, pre-existing liver disease, doses >3 g/day. Nicotinamide is generally hepatically safer. Sustained-release formulations should be avoided in patients with liver disease.