Pyridoxine Hydrochloride

Pronunciation: peer-ih-DOX-een HIGH-droe-KLOR-ide
Class: Vitamin, water-soluble

Trade Names

Pyridoxine Hydrochloride
- Tablets 10 mg
- Tablets 25 mg
- Tablets 50 mg
- Tablets 100 mg
- Tablets 200 mg
- Tablets 250 mg
- Tablets, extended-release 200 mg
- Capsules 500 mg
- Solution 200 mg per 5 mL

Pyri-500
- Tablets 500 mg

Rodex
- Capsules 150 mg

Vitabee-6
- Injection 100 mg/mL

Pharmacology

Vitamin B ₆ functions as coenzyme in amino acid, carbohydrate, and lipid metabolism.

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Pharmacokinetics

Absorption

Absorbed by passive diffusion in the jejunum and to a lesser extent in the ileum.

Distribution

Primarily stored in the liver, lesser amount in the muscle and brain. Not protein bound.

Metabolism

Metabolized in the liver and converted to 4-pyridoxic acid metabolite.

Elimination

Excreted mostly as 4-pyridoxic acid in the urine. The t _½ is 15 to 20 days.

Indications and Usage

Pyridoxine deficiency, including inadequate diet, drug-induced causes (eg, isoniazid, hydralazine, oral contraceptives) or inborn errors of metabolism. Parenteral use is indicated when oral therapy is not feasible.

Unlabeled Uses

Treatment of hydrazine poisoning, PMS, hyperoxaluria type I, nausea and vomiting in pregnancy, sideroblastic anemia associated with high serum iron, carpal tunnel syndrome, tardive dyskinesia.

Contraindications

Standard considerations.

Dosage and Administration

PO / IM / IV 10 to 20 mg/day for 3 wk.

PO / IM / IV 100 to 200 mg/day for 3 wk; follow with 25 to 100 mg/day.

PO / IM / IV 50 to 200 mg/day.

PO / IM / IV 600 mg, followed by 30 mg/day for life. Dependency has been noted in adults administered 200 mg/day.

IM / IV 10 to 100 mg, followed by 2 to 100 mg/day.

PO / IM / IV 100 to 500 mg/day.

IV 4 g IV followed by 1 g IM every 30 min until pyridoxine dose equal to isoniazid dose has been given.

General Advice

• Instruct patient to swallow enteric-coated preparation whole and not to break, crush or chew.
• When giving via IM route, rotate sites.
• IV preparation may be given undiluted or added to standard compatible IV solutions.

Storage/Stability

Store all forms of drug at room temperature in tightly closed, light-resistant containers. Avoid freezing injection.

Drug Interactions

Increased need for pyridoxine.

Decreased effect of levodopa. (Interaction does not occur with levodopa/carbidopa in combination with pyridoxine.)

Phenytoin serum levels may be decreased.

Incompatibility

Incompatible with alkaline solutions, iron salts and oxidizing agents (parenteral).

Laboratory Test Interactions

May result in false-positive urobilinogen in the spot test using Ehrlich reagent.

Adverse Reactions

CNS

Neuropathy; unstable gait; drowsiness; somnolence.

EENT

Perioral numbness.

Miscellaneous

Numbness of feet; decreased sensation to touch, temperature or vibration; paresthesia; low serum folic acid levels; burning/stinging at IM injection site; photoallergic reaction; ataxia.

Precautions

Pregnancy

Category A . ( Category C in doses that exceed the RDA.)

Lactation

Excreted in breast milk; may inhibit lactation.

Children

Safety and efficacy not established in doses exceeding nutritional requirements.

Overdosage

Symptoms

Ataxia, sensory neuropathy.

Patient Information

• Emphasize importance of complying with prescribed dietary recommendations.
• Teach patient about foods high in B ₆ (whole grain cereals, meat [eg, liver], potatoes, green vegetables, legumes [eg, lima beans], yeast and bananas).
• If patient is self-medicating with vitamin supplements, caution that megadosing may cause adverse reactions such as unsteady gait, impaired hand coordination and numbness of feet.

Copyright © 2009 Wolters Kluwer Health.