Vitamin B₃ (Niacin, Nicotinic Acid)

Category:

• Vitamin

Description:

• Dietary supplement; water-soluble vitamin

  Indications:

• Vitamin B₃ deficiency

  • necessary for cholesterol control, electron transfer

• Pellegra (characterized by the three “Ds”: diarrhea, dermatitis, dementia)

• Hyperlipidemia

Contraindications:

• Hepatic dysfunction

• Active peptic ulcer disease

Precautions:

• Pregnancy category A, (pregnancy category C if given above RDA doses)

• Do not administer with HMG-CoA reductase inhibitors (lovastatin, simvastatin, etc.) due to risk of rhabdomyolysis.

• Monitor liver function tests and blood glucose (especially diabetic patients)

• May increase uric acid levels and precipitate gout.

• Flushing appears more frequently with oral therapy and generally occurs within the first two hours of administration.  Flushing may be decreased if 325mg aspirin is administered 30-60 minutes pre-niacin dosing.

Adverse Reactions (Side Effects):

• Relatively non-toxic dietary doses

• At higher doses:

  • facial and generalized flushing (within first 2 hours), rash, itching, dry skin, pruritis

  • GI distress, activation of peptic ulcers, nausea, vomiting, diarrhea

  • hepatotoxicity

Dosage:

• Dietary sources: lean meat, fish, cereals, grains, legumes, conversion of dietary trytophan

• Administered orally (tablets, capsules, sustained-release, elixir) or injection

• Dietary supplementation (RDA: recommended daily allowance):

  • 6.6mg per 1000Kcal intake

  • Adult males: 19mg per day

  • Adults females: 15mg per day

• Niacin deficiency: up to 100mg per day

• Pellegra: up to 500mg per day

• Hyperlipidemia: 1-2 grams tid (do not exceed 6 grams per day)