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• Treatment and prevention of pyridoxine deficiency (may be associated with poor nutritional status or chronic debilitating illnesses).
• Treatment of pyridoxine-dependent seizures in infants.
• Treatment and prevention of neuropathy, which may develop from isoniazid, penicillamine, or hydralazine therapy.
• Management of isoniazid overdose >10 g.

• Required for amino acid, carbohydrate, and lipid metabolism.
• Used in the transport of amino acids, formation of neurotransmitters, and synthesis of heme.

• Prevention of pyridoxine deficiency.
• Prevention or reversal of neuropathy associated with hydralazine, penicillamine, or isoniazid therapy.

Absorption: Well absorbed from the GI tract.

Distribution: Stored in liver, muscle, and brain. Crosses the placenta and enters breast milk.

Metabolism/Excretion: Converted in RBCs to pyridoxal phosphate and another active metabolite. Amounts in excess of requirements are excreted unchanged by the kidneys.

Half-life: 15–20 days.

Contraindicated in:

• Hypersensitivity to pyridoxine or any component.

Use Cautiously in:

• Parkinson’s disease (treatment with levodopa only)
• OB: Chronic ingestion of large doses may produce pyridoxine-dependency syndrome in newborn.

Adverse reactions listed are seen with excessive doses only

Neuro: sensory neuropathy, paresthesia.

Misc: pyridoxine-dependency syndrome.

Drug-Drug:

• Interferes with the therapeutic response to levodopa when used without carbidopa.
• Requirements are increased by isoniazid, hydralazine, chloramphenicol, penicillamine, estrogens, and immunosuppressants.
• Decreases serum levels of phenobarbital and phenytoin.

Prevention of Deficiency (Recommended Daily Allowance)

• PO (Adults and Children >14 yr): 1.2–1.7 mg/day (larger doses required with cycloserine, ethionamide, hydralazine, immunosuppressants, isoniazid, penicillamine, and estrogen-containing oral contraceptives).
• PO (Children 9–13 yr): 1 mg/day (larger doses required with cycloserine, ethionamide, hydralazine, immunosuppressants, isoniazid, and penicillamine).
• PO (Children 1–8 yr): 0.5–0.6 mg/day (larger doses required with cycloserine, ethionamide, hydralazine, immunosuppressants, isoniazid, and penicillamine).
• PO (Infants 6–12 mo): 0.3 mg/day.
• PO (Infants <6 mo): 0.1 mg/day.

Treatment of Deficiency

• PO (Adults): 2.5–10 mg/day until clinical signs are corrected, then 2–5 mg/day.
• PO (Children): 5–25 mg/day for 3 wk, then 1.5–2.5 mg/day.

Pyridoxine-Dependent Seizures

• PO, IM, IV (Neonates and Infants): 10–100 mg initially then 50–100 mg/day orally.

Drug-Induced Neuritis

• PO (Adults): Treatment — 100–300 mg/day; Prophylaxis — 25–100 mg/day.
• PO (Children): Treatment — 10–50 mg/day; Prophylaxis — 1–2 mg/kg/day.

Isoniazid Overdose (>10 g)

• IM, IV (Adults and Children): Amount in mg equal to amount of isoniazid ingested given as 1–4 g IV, then 1 g IM every 30 min.

• High Alert:Do not confuse pyridoxine with Pyridium (phenazopyridine).
• Because of infrequency of single B-vitamin deficiencies, combinations are commonly administered.
  • Administration of parenteral vitamin B₆ is limited to patients who are NPO or who have nausea and vomiting or malabsorption syndromes.
  • Protect parenteral solution from light; decomposition will occur.
• PO: Extended-release capsules and tablets should be swallowed whole, without crushing, breaking, or chewing. For patients unable to swallow capsule, contents of capsules may be mixed with jam or jelly.
• IM: Rotate sites; burning or stinging at site may occur.
• IV: May be administered slowly by IV push or as infusion in standard IV solutions. Monitor respiratory rate, heart rate, and BP when administering large IV doses.
  • Pyridoxine-dependent seizures should cease within 2–3 min of IV administration.
• Rate: Infusion rates of 15–30 min and up to 3 hr have been used.
• Additive Incompatibility:
  • alkaline solutions
  • riboflavin

Neuro-K–250 TD, Neuro-K-250 Vitamin B6, Neuro-K-50, Neuro-K-500, Pyri 500, vitamin B₆

Therapeutic Classification: vitamins

Pharmacologic Classification: water soluble vitamins

(Generic available)

• Capsules: 250 mg^OTC;
• Tablets: 25 mg^OTC; 50 mg^OTC; 100 mg^OTC; 250 mg^OTC; 500 mg^OTC;
• Extended-release tablets: 200 mg^OTC; 500 mg^OTC;
• Injection: 100 mg/mL;
• In combination with: vitamins, minerals, and trace elements in a variety of multivitamin preparations^OTC.