Medical Care
Levels of pyridoxine hydrochloride supplementation in various medical conditions are as follows:
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Cirrhosis - 50 mg/d
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Hemodialysis - 5-50 mg/d
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Peritoneal dialysis - 2.5-5 mg/d
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Chronic renal failure - 2.5-5 mg/d
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Sideroblastic anemia - 50-600 mg/d
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Pyridoxine-dependent seizures - 100 mg/d
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Homocystinuria - 100-500 mg/d
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Homocystinemia - 100-500 mg/d
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Gyromitra poisoning - 25 mg/kg IV
At one time, pyridoxine supplementation was given to people with sickle cell anemia; however, no changes were noted in these patients' hematologic indexes or disease activity.
Diet and Activity
Diet
Pyridoxine is widespread in foods. Rather robust quantities can be found in meats, particularly liver, fish, and chicken; vegetables, particularly beans, peas, and tomato; fruits, such as oranges, bananas, and avocados; and grains, such as enriched breads, cereals, and grains.
Some vegetables contain up to 70% biologically unavailable pyridoxine as pyridoxine-5-glucoside.
Some heat-treated foods may contain pyridoxine-lysine, which has antivitamin activity.
The minimum daily requirement of pyridoxine is approximately 1.5 mg; however, the recommended daily intake by the US National Research Council is 2 mg for adults and 0.3 mg for infants.
A lysine-restricted diet appears to be well tolerated and results in improved development and metabolic biomarkers in children with a mutation in the ALDH7A1 (antiquitin) gene and pyridoxine-dependent seizures. [20]
Activity
Vigorous exercise results in a transient increase in plasma PLP, probably from the release of muscular glycogen phosphate. Carbohydrate loading prior to exercise reduces this response. Within 30 minutes of discontinuing exercise, PLP levels return to normal.
Prevention
Prophylactic administration of pyridoxine should be provided when a patient is using certain medications, such as isoniazid (30-450 mg/d, which may be based gram for gram) and penicillamine (100 mg/d).
Estrogen-induced reduction in tryptophan metabolism may require supplementation of 20-25 mg/d.
