megavitamin therapy (redirected from Niacin/nicotinic acid & niacinamide/nicotinamide)

megavitamin therapy

[-vī′təmin]

a type of treatment that involves the administration of large doses of certain vitamins and minerals.

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megavitamin therapy

The administration of excess or 'hyper-doses' of water-soluble vitamins, either physician-guided–eg, to treat neuropathies, or self-prescribed by health-food advocates. See Decavitamin, Orthomolecular medicine, Vitamin.

Megavitamins, adverse effects  

Thiamin CNS hyperresponsiveness–convulsions, Parkinson's disease–thiamin antagonizes l-dopa, sensory neuropathy–destruction of dorsal axon roots

Niacin/nicotinic acid & niacinamide/nicotinamide Exacerbation of asthma–histamine release, cardiac disease–arrhythmias, GI symptoms, eg nausea, vomiting, diarrhea, anorexia, DM–hyperglycemia, gout–↑ uric acid, liver disease–enzyme leakage, hepatocellular injury, portal fibrosis or massive necrosis, cholestatic jaundice, peptic ulcer disease–histamine release, ↑ acidity, skin disease

Vitamin B₆ Paresthesia, headaches, asthenia, irritability

Vitamin C ↑ Iron absorption, possibly iron overload, evoking diarrhea, renal calculus formation and possibly inhibiting the bacteriolytic activity of neutrophils, G6PD deficiency–↑ red cell lysis, megaloblastic anemia–↓ vitamin B₁₂ absorption, nephrolithiasis–oxaluria Diagn Clin Testing 1990; 28:27