Simultaneous use of pyridoxine with amiodarone can increase the risk of drug-induced sensitivity to sunlight , and pyridoxine can decrease the effects of phenytoin and phenobarbital. A deficiency has not been seen in humans on a normal diet because it is so widely distributed in foods, however it is often included in multivitamin preparations. There is insufficient information to establish RDAs for pantothenic acid. The Committee on Dietary Allowances provides provisional recommendations for adults of 4 to 7 mg. per day. Folic acid deficiency is a common complication of diseases of the small intestine that interfere with the absorption of folic acid from food and the recycling of folic acid from the liver back to the intestines.
Alcoholism can result in folic acid deficiency.
The simultaneous ingestion of folic acid supplements may, in theory, interfere with the effectiveness of methotrexate cancer treatments , however their combined use in the treatment of rheumatoid arthritis and psoriasis has resulted in lessened side effects from methotrexate. Excessive doses of folic acid may mask the anemia that results from B 12 deficiency, preventing diagnosis of the deficiency and allowing progression of neurological damage. Adequate folic acid intake is associated with a reduced risk of neural tube birth defects. It is recommended that all women of childbearing age consume at least 400 micrograms of folic acid each day. Folic acid supplements are also used to lower elevated homocysteine levels, a known risk factor for heart disease.