Niacinamide
Nicotinamide
Also known as: Vitamin PP · Niacinamide · Nicotinamide · Nicotinamidum · Nicotinic acid amide · Nicotylamide · Vitamin B3 amide
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Discoid lupus erythematosus | For dogs weighing 10 kg or more: 500 mg of niacinamide and 500 mg of tetracycline PO q8h. For dogs weighing from 5-10 kg: 250 mg of each drug PO q8h. For dogs weighing less than 5 kg: 100 mg of each drug PO q8h. | PO | q8h | Improvement usually noted within 6 weeks | 🌎 NA |
| Discoid lupus erythematosus or pemphigus | Dogs weighing more than 10 kg: 500 mg of niacinamide and 500 mg of tetracycline PO q8h. For dogs weighing less than 10 kg: 250 mg of each PO q8h. | PO | q8h | — | 🌎 NA |
| Various immune-mediated diseases (DLE, pemphigus, vasculitis, dermatomyositis, etc.) | For dogs less than 10 kg: 250 mg each of niacinamide and tetracycline PO three times daily. For dogs larger than 10 kg: 500 mg each of niacinamide and tetracycline PO three times daily. | PO | TID | — | 🌎 NA |
| Pemphigus foliaceous | Doses as above (with prednisone and azathioprine). Once remission has occurred the dose may be gradually tapered to once daily administration. | PO | TID initially, taper to q24h | Improvement within 1-2 months | 🌎 NA |
| Adjunctive therapy for pemphigus or discoid lupus erythematosus | 100 mg of each for dogs <5kg; 250 mg of each for dogs 5-10 kg; 500 mg of each for dogs >10 kg PO three times daily until resolve (90-120 days), then decrease by one dose per day per month (three times daily to two times daily to once daily and eventually to every other day for 30-60 days.) | PO | TID initially, then tapered | 90-120 days initially, then 30-60 days taper | 🌎 NA |
| Immunomodulation (e.g., lupoid onychodystrophy, discoid lupus erythematosus, pemphigus foliaceus) | 250 mg/dog (dogs up to 25 kg), 500 mg/dog (dogs >25 kg) | PO | q8h | Taper to effect | 🌍 EU |
- Discoid lupus erythematosus: Given in combination with tetracycline.
- Discoid lupus erythematosus or pemphigus: May use in combination with corticosteroids and Vitamin E. If adverse effects become a problem, reduce dose of niacinamide first.
- Various immune-mediated diseases (DLE, pemphigus, vasculitis, dermatomyositis, etc.): May substitute doxycycline for tetracycline at 5 mg/kg PO once a day.
- Pemphigus foliaceous: Used as adjunctive therapy.
- Adjunctive therapy for pemphigus or discoid lupus erythematosus: Given with tetracycline.
- Immunomodulation (e.g., lupoid onychodystrophy, discoid lupus erythematosus, pemphigus foliaceus): Often used in combination with oxytetracycline, tetracycline, or doxycycline.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Niacinamide (also known as nicotinamide) is the water-soluble amide form of Vitamin B3. While it functions as an essential nutrient for tissue respiration and lipid metabolism, its primary use in veterinary pharmacology is as an immunomodulator.
In canine medicine, it is most frequently prescribed in synergistic combination with tetracycline (or doxycycline) to manage immune-mediated dermatologic conditions. It is particularly effective for discoid lupus erythematosus (DLE) and pemphigus erythematosus, showing efficacy in 25% to 65% of affected dogs.
Clinical Pearl: It is critical to distinguish niacinamide from niacin (nicotinic acid). Unlike niacin, niacinamide does not cause cutaneous vasodilation (the "niacin flush") and does not affect blood lipid levels or the cardiovascular system, making it the appropriate and safe choice for long-term immunomodulation in dogs.
Mechanism of action
At pharmacologic doses, niacinamide exerts anti-inflammatory and immunomodulatory effects through several pathways:
- Mast Cell Stabilization: Blocks IgE-induced histamine release and prevents the degranulation of mast cells.
- Enzyme Inhibition: Inhibits phosphodiesterase (PDE) enzymes → increases intracellular cAMP → decreases the release of inflammatory proteases.
- Synergy with Tetracyclines: When used concurrently with tetracycline or doxycycline, the combination suppresses leukocyte chemotaxis that occurs secondary to complement activation by antibody-antigen complexes.
- Nutritional Role: Acts as a precursor to NAD and NADP, essential coenzymes for tissue respiration, glycogenolysis, and lipid metabolism.
Safety & warnings
Contraindications
- Liver disease
- Active peptic ulcers
- Hypersensitivity to niacinamide
- Do not use nicotinic acid (niacin) as a substitute due to severe vasodilation (flushing) effects.
Adverse effects
- Lethargy
- Elevated liver enzymes (occasional)
- Increased seizure frequency (anecdotal)
- Mild gastrointestinal irritation (anorexia, vomiting, diarrhea)
Precautions
Use with caution in dogs with a history of seizures. While niacinamide alone is generally considered safe in pregnant and lactating animals, its common concurrent use with tetracycline may not be safe during pregnancy/nursing.
Drug interactions
May require dosage adjustments after initiating niacinamide therapy due to potential alterations in glycemic control.
May require dosage adjustments after initiating niacinamide therapy.
Monitoring
- Clinical efficacy (resolution of dermatologic lesions)
- Adverse effects (GI upset, lethargy)
- Liver enzymes (baseline and occasional monitoring suggested)
- Clinical resolution of dermatological lesions
- Gastrointestinal signs (vomiting, diarrhea, anorexia)
- Liver enzymes (if used long-term or at high doses)
Pharmacokinetics
Half-life
Absorption
Absorbed well after oral administration.
Distribution
Widely distributed to body tissues.
Metabolism
Metabolized in the liver to several metabolites.
Elimination
Excreted into the urine. At physiologic doses, only a small amount is excreted unchanged, but as dosages increase, larger quantities are excreted unchanged.
Overdose
Acute toxicity is rare. Overdoses are unlikely to cause significant problems other than acute gastrointestinal distress (vomiting, diarrhea).
Available products
Formulations
- Tablets
- 250 mg oral tablet
Human-labeled
- Niacinamide (Nicotinamide) Tablets: 100 mg & 500 mg (OTC)
- Nicotinamide 50 mg tablets
- Nicotinamide 250 mg tablets
Regulatory status
Available as general sale.
Available as general sale.
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store tablets in tight containers at room temperature unless otherwise labeled. Incompatible with alkalis or strong acids.
Client information
- Give exactly as directed: This medication is usually given alongside an antibiotic (like tetracycline or doxycycline) to treat immune-mediated skin conditions.
- Be patient: It often takes 6 to 8 weeks (sometimes up to 2 months) to see noticeable improvement in your dog's skin.
- Watch for side effects: Contact your veterinarian if your dog experiences vomiting, loss of appetite, or unusual tiredness.
- Do not substitute: Ensure you are using niacinamide (or nicotinamide) and NOT niacin (nicotinic acid), as niacin can cause uncomfortable flushing and other side effects.
- Do not stop the medication abruptly once the skin looks better; your veterinarian will likely provide a tapering schedule.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.