Yes

Vitamin, Water Soluble

Prophylaxis and treatment of pellagra

A (C if used in doses greater than RDA suggested doses)

Hypersensitivity to niacin or niacinamide; liver disease; active peptic ulcer; severe hypotension; arterial hemorrhage

Use caution in heavy ethanol users, unstable angina or CAD (risk of arrhythmias at high doses), diabetes (interfere with glucose control), renal disease, active gallbladder disease (can exacerbate), gout, or allergies. Avoid large pharmacological amounts in patients with a history of liver disease. Monitor liver function tests with high doses.

Percentage unknown: Tachycardia, rash, bloating, flatulence, nausea, paresthesia in extremities, blurred vision, wheezing, increased sebaceous gland activity

Symptoms of overdose include GI distress

Treatment is supportive

Oral hypoglycemics: Effect may be decreased by niacin.

Sulfinpyrazone and probenecid; niacin may inhibit uricosuric effects.

Aspirin decreases adverse effect of flushing.

Lovastatin (and possibly other HMG CoA reductase inhibitors): Increased risk of toxicity (myopathy).

Adrenergic blocking agents additive vasodilating effect and postural hypotension.

Used by the body as a source of niacin; is a component of two coenzymes which is necessary for tissue respiration, lipid metabolism, and glycogenolysis; inhibits the synthesis of very low density lipoproteins; does not have hypolipidemia or vasodilating effects

Absorption: Rapid from GI tract

Metabolism: In the liver

Half-life: 45 minutes

Time to peak serum concentration: 20-70 minutes

Elimination: In urine

Oral:

Adults: 50 mg 3-10 times/day

Pellagra: 300-500 mg/day

Recommended daily allowance: 13-19 mg/day

False elevations of urinary catecholamines in some fluorometric determinations

None noted

None noted

No information available to require special precautions

No effects or complications reported

Tablet: 50 mg, 100 mg, 125 mg, 250 mg, 500 mg

Gugler R, "Clinical Pharmacokinetics of Hypolipidaemic Drugs," Clin Pharmacokinet, 1978, 3(6):425-39.

LeWitt PA, "The Neurotoxicity of the Rat Poison Vacor. A Clinical Study of 12 Cases," N Engl J Med, 1980, 302(2):73-7.

Ovesen L, "Vitamin Therapy in the Absence of Obvious Deficiency: What Is the Evidence?" Drugs, 1984, 27(2):148-70.