What is the treatment for pyridoxine (Vitamin B6) deficiency?

Treatment of Pyridoxine (Vitamin B6) Deficiency

For pyridoxine deficiency, oral supplementation with 50-100 mg daily for one to two weeks is the recommended treatment for deficiency resulting from chronic poor dietary intake. 1

Diagnosis

Before initiating treatment, confirm the diagnosis by:

• Measuring plasma pyridoxal phosphate (PLP) levels, which is the standard method for determining vitamin B6 status
• In patients with inflammation or serious illness, red cell PLP should be measured instead 1
• Normal plasma PLP values range from 5-50 μg/L (20-200 nmol/L)

Treatment Protocol

Oral Supplementation

• For dietary deficiency: 50-100 mg daily for 1-2 weeks, followed by maintenance dose of 2-5 mg daily 1, 2
• For maintenance therapy: After initial treatment, continue with a daily multivitamin containing 2-5 mg pyridoxine 2

Parenteral Administration

• When oral administration is not feasible (anorexia, nausea, vomiting, impaired GI absorption, or perioperative conditions):
  • 10-20 mg daily intramuscularly or intravenously for 3 weeks 2
  • Follow with oral maintenance therapy

Special Clinical Scenarios

1. Isoniazid-induced deficiency:

   • 100 mg daily for 3 weeks followed by 30 mg maintenance dose daily 2
   • For isoniazid overdose: Administer pyridoxine equal to the amount of isoniazid ingested (1 g IV for each gram of isoniazid, then 1 g IM/IV every 30 minutes up to 5 g maximum) 1

2. Vitamin B6 dependency syndromes:

   • May require up to 600 mg daily initially
   • Followed by lifelong maintenance of 30 mg daily 2

3. Patients with chronic kidney disease:

   • Hemodialysis patients: 10 mg/day of supplemental pyridoxine hydrochloride 3
   • Peritoneal dialysis and non-dialyzed CKD patients: 5 mg/day 3
   • Higher doses (10 mg/day) may be needed during sepsis or when taking vitamin B6 antagonists 3

4. Pyridoxine-dependent epilepsy:

   • Initial dose: 100 mg IV (with respiratory support available)
   • Long-term: 15-30 mg/kg/day in infants, up to 200 mg/day in neonates, and 500 mg/day in adults 4

5. Ethylene glycol poisoning:

   • 50 mg IV every 6 hours 1

Nutritional Requirements in Specific Settings

• Enteral nutrition: Should deliver at least 1.5 mg pyridoxine per day in 1500 kcal 1
• Parenteral nutrition: Should deliver 4-6 mg pyridoxine per day 1

Monitoring and Follow-up

• PLP levels respond to intake within 6-10 days, reflecting liver stores 1
• Monitor for resolution of clinical symptoms:
  • Seborrheic dermatitis
  • Cheilosis and glossitis
  • Microcytic anemia
  • Neurological symptoms (convulsions, confusion, depression)

Caution: Toxicity Risk

• Long-term high-dose supplementation can cause sensory neuropathy
• Doses >500 mg/day have resulted in various side effects 1
• Negative effects reported with prolonged intake of 300 mg/day
• Long-term doses as low as 100 mg/day have been associated with Lhermitte signs (spinal cord effects) 1, 5
• Symptoms of toxicity include sensory neuropathy with ataxia, areflexia, impaired sensations, and dermatologic lesions 1

Prevention in High-Risk Groups

Prophylactic pyridoxine (25-50 mg/day) should be given to all persons at risk of neuropathy when receiving isoniazid therapy, including:

• Pregnant women
• Breastfeeding infants
• Persons with HIV
• Patients with diabetes, alcoholism, malnutrition, or chronic renal failure
• Elderly patients 1

For patients with peripheral neuropathy, increasing pyridoxine dose to 100 mg/day is recommended 1.

By following these guidelines, pyridoxine deficiency can be effectively treated while minimizing the risk of toxicity from excessive supplementation.