ASK DIS: Vitamin B- Complex Maximum Dosing

Dosing

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:

ASK DIS