Thursday, July 9, 2015

Vitamin B- Complex Maximum Dosing

  • Aneurine (Thiamine/B1) = 1.0mg
  • Riboflavin (B2) = 1.5mg
  • Nicotinamide (B3) = 10.0mg
Dosing
  • Product leaflet recommends 1-2 tab OD
  • There is no information regarding maximum doses
Analysis based on individual components

Aneurine/Thiamine
  • Because of the lack of reports of adverse effects from high thiamin intakes (50 mg/day or more) from food or supplements, the FNB did not establish upper limits for thiamin
  • They hypothesize that the apparent lack of toxicity may be explained by the rapid decline in absorption of thiamin at intakes above 5 mg. 
  • However, the FNB noted that in spite of the lack of reported adverse events, excessive intakes of thiamin could have adverse effects
Riboflavin
  • Treatment of Deficiency: Adults PO 5 to 10 mg/day. Children PO 2 to 10 mg/day
  • Intakes of riboflavin from food that are many times the RDA have no observable toxicity, possibly because riboflavin's solubility and capacity to be absorbed in the gastrointestinal tract are limited 
  • Because adverse effects from high riboflavin intakes from foods or supplements (400 mg/day for at least 3 months) have not been reported, the FNB did not establish Upper limits for riboflavin

Nicotinamide/Niacin

  • Not many evidence on doisng
  • Based on some available products (750mg), nicotinamide was recommended to be given up to 1.5g (in 2 divided dose)
  • some recommends 10-20mg daily, and up to a maximum of 100mg for niacin deficiency. 
  • higher doses are recommended for managemnet of pellagra. a dose of  50 to 100 mg orally 3 to 4 times a day, with a maximum recommended dose of 500 mg orally each day.
  • High-dose nicotinamide should still, however, be considered as a drug with toxic potential at adult doses in excess of 3 gm/day and unsupervised use should be discouraged
Recommendation
  • Based on our product and KKM formulary, we recommend 1-2 tab daily.
  • For higher dosages, it should be initiated base on the indication and dietary need
  • Taking riboflavin as the dose limiting drug (10mg), a dose up to 6 tab in a day can be given based on limited amount of evidence
References:
  1. KKM Drug Formulary
  2. http://ods.od.nih.gov/factsheets/Thiamin-HealthProfessional/
  3. http://ods.od.nih.gov/factsheets/Riboflavin-HealthProfessional/
  4. http://link.springer.com/article/10.1007%2Fs001250051536
  5. http://www.drugs.com/drp/nicotinamide.html
  6. http://www.drugs.com/niacin.html
  7. http://www.vitaminbcomplex.org/daily-requirement-and-dose/

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