Vitamin B6 Side Effects and Warnings

Safety Issues

The safe upper levels for daily intake of vitamin B 6 ¹ are as follows:

• Children
• 1-3 years: 30 mg
• 4-8 years: 40 mg
• Males and Females
• 9-13 years: 60 mg
• 14-18 years: 80 mg
• 19 years and older: 100 mg
• Pregnant or Nursing Women
• 18 years old and younger: 80 mg
• 19 years and older: 100 mg

At higher dosages (especially above 2 g daily) there is a very real risk of nerve damage. Nerve-related symptoms have even been reported at doses as low as 200 mg.² (This is a bit ironic, given that B6 deficiency also causes nerve problems.) In some cases, very high doses of vitamin B6 can cause or worsen acne symptoms.⁴

In addition, doses of vitamin B6 over 5 mg may interfere with the effects of the drug levodopa when it is taken alone.^{6, 7} However, vitamin B6 does not impair the effectiveness of drugs containing levodopa and carbidopa.

Maximum safe dosages for individuals with severe liver or kidney disease have not been established.

Interactions You Should Know About

If you are taking:

• Isoniazid (INH) , penicillamine , hydralazine , theophylline , or MAO inhibitors : You may need extra vitamin B 6 , but take only nutritional doses. Higher doses of B 6 might interfere with the action of the drug.

• Levodopa without carbidopa (for Parkinson's disease): Do not take more than 5 mg of vitamin B 6 daily, except on medical advice.

• Antipsychotic medications: B 6 might reduce side effects.

1. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (1998). Available at www.nap.edu. Accessed October 4, 2001.

Vitamin B6 Side Effects and Warnings