Niacin

Niacin (Nicotinic Acid, Niacinamide, Vitamin B3) is a B Vitamin
1. As a component of NADH and NADPH, is involved in many in vivo reactions
2. Niacin may be ingested or synthesized from Tryptophan (Essential Amino Acid)
Food sources of Niacin
1. Wheat germ
2. Liver
3. Fish
4. Peanuts
Niacin Deficiency (Pellagra)
1. Sythesized from Tryptophan and deficiency may be seen in limited diets (e.g. corn) in which Tryptophan is absent
2. Pellagra presents with Diarrhea, Dermatitis and Dementia (3D's)

Older indications that should be reconsidered in light of AIM-High Study (Niacin did not appear effective in these cases)
1. Low HDL Cholesterol
2. Combination therapy with Statin for Hyperlipidemia
Indications that are reasonable as of 2013
1. Hypertriglyceridemia
2. Hyperlipidemia Management in patients intolerant to Statins

HDL increased (15-35%)
1. No other agent raises HDL as much as Niacin
2. However Niacin related HDL increase did not effect outcomes in 2011 AIM-HIGH study (prematurely stopped)
Triglycerides decreased (20-50%)
LDL Cholesterol decreased (10-25%)
1. Significantly lowers LDL only at high dose
2. Not a first-line agent for lowering LDL

Does not affect all cause mortality
Statin with Niacin did not show benefit beyond Statin alone in AIM-HIGH study (2011)
Studies since the 1980s to today have suggested coronary disease risk reduction, but benefit may be aside from affect on HDL Cholesterol
1. Canner (1986) J Am Coll Cardiol, 8:1245 [PubMed]
2. Lavigne (2013) J Am Coll Cardiol 61(4):440-6. [PubMed]

Flushing
Pruritus
Skin irritation of neck and face
Gastrointestinal upset (Dyspepsia, Diarrhea)
Blurred Vision
Fatigue
Glucose intollerance
Hyperuricemia and gout
Peptic Ulcer Disease exacerbation
Hepatic toxicity with sustained release forms
Diabetes Mellitus (when Niacin is combined with a Statin)
1. Increases risk of developing diabetes or worsening diabetes control
2. (2014) N Engl J Med 2014 371:203-12 [PubMed]

Poor Compliance: 40% discontinue use
Reduced Flushing and Pruritus reaction
1. Use Aspirin or Ibuprofen pretreatment
2. Take dose with food

Crystalline Niacin
1. Dose: 1g PO tid ($5.50/mo) MAX: 6 g/day
2. Example protocol (Use 500 mg tablets)
  1. Start: 250 mg at bedtime
  2. Titrate up over 6 weeks to 500 mg tid
3. Pretreatment: Aspirin 81 mg before or Ibuprofen
Niaspan (preferred)
1. Safest of Niacins (only 4% GI side effects)
2. More expensive than crystalline Niacin
3. Example protocol for initiating doses
  1. One 500 mg tablet PO qhs for 1 month
  2. Two 500 mg tablets PO qhs for 1 month
  3. One 1000 mg tablet PO qhs for 1 month
  4. Check lFTs, Uric Acid, Glucose at 3 months
  5. Two 1000 mg tablets PO qhs
4. References
  1. McBride (2003) New Therapeutics Lecture, Cable, WI
Agents to avoid
1. Avoid flush-free or no-flush Niacin
2. Avoid Slow Niacin (Sustained Release)
  1. Decreased Safety due to hepatotoxicity