Treatment of Vitamin B6 Deficiency

Diagnosis and Treatment

The American College of Nutrition recommends oral supplementation with 50-100 mg of pyridoxine daily for one to two weeks for chronic vitamin B6 deficiency resulting from poor dietary intake 1, 2
Vitamin B6 status should be determined by measuring plasma pyridoxal phosphate (PLP) levels, with normal values ranging from 5-50 mg/L (20-200 nmol/L) 3
In seriously ill patients or those with inflammation, red cell PLP should be measured instead of plasma levels as it provides more reliable results 2, 3
PLP levels respond to intake and reflect liver stores, typically plateauing in 6-10 days 1

For deficiency resulting from chronic poor dietary intake, oral supplements of 50-100 mg for one to two weeks are safe and widely available 1, 2
In isoniazid overdose-induced seizures, administer 1 g of pyridoxine for each gram of isoniazid ingested, up to 5 g maximum (given 1 g IV/IM every 30 minutes) 1
For ethylene glycol poisoning, pyridoxine is recommended at 50 mg IV every 6 hours 1

Enteral nutrition should deliver at least 1.5 mg pyridoxine per day in 1500 kcal (Grade A recommendation) 1
Parenteral nutrition should deliver 4-6 mg pyridoxine per day (Grade B recommendation) 1

Monitor for toxicity signs, which include sensory neuropathy with ataxia or areflexia, impaired cutaneous and deep sensations, and dermatologic lesions 1
Long-term doses as low as 100 mg/day have been associated with Lhermitte signs (effect on the spinal cord) 1
Avoid prolonged intake of >300 mg/day due to potential negative effects 1

Alcoholics are at high risk for vitamin B6 deficiency 1, 2
Renal dialysis patients are at high risk for vitamin B6 deficiency 1, 2
Elderly individuals are at high risk for vitamin B6 deficiency 1, 2
Post-operative patients are at high risk for vitamin B6 deficiency 1, 2
Patients with infections or critical illness are at high risk for vitamin B6 deficiency 1, 2
Pregnant women are at high risk for vitamin B6 deficiency 1, 2
Patients receiving medications that inhibit vitamin B6 activity (isoniazid, penicillamine, anti-cancer drugs, corticosteroids, anticonvulsants) are at high risk for vitamin B6 deficiency 1, 2, 4
Patients with HIV infection on therapy are at high risk for vitamin B6 deficiency 2
Patients with severe alcoholic hepatitis are at high risk for vitamin B6 deficiency 2