Class: Vitamin B Complex
VA Class: VT109
Chemical Name: 2-methyl-3-hydroxy-4,5-bis (hydroxymethyl) pyridine hydrochloride
CAS Number: 58-56-0
Water-soluble, B complex vitamin.a
Uses for Pyridoxine Hydrochloride
Treatment of vitamin B6 deficiency.a b
Adequate intake needed to prevent vitamin B6 deficiency.157
Adequate intake of pyridoxine can be accomplished through consumption of fortified ready-to-eat cereals; meals containing substantial portions of meat, fish, or poultry; white potatoes and other starchy vegetable; and noncitrus fruits.157
Recommended Dietary Allowance (RDA) in adults based on a plasma pyridoxal phosphate concentration of 5 ng/mL.157
Adequate intake (AI) established for infants ≤6 months of age based on observed mean vitamin B6 intake of infants fed principally human milk; AI for infants 7–12 months of age based on AI for younger infants and data in adults.157
RDA for children 1–18 years of age based on data in adults.157
Treatment of pyridoxine-dependent seizures.159 a b
Xanthurenic aciduria, cystathioninuria, and homocystinuria resulting from genetic abnormalities may respond to high doses of pyridoxine.a
Prevention or Treatment of Drug-induced Neurotoxicity
Prevent or treat neuropathy in patients receiving isoniazid.a b Pyridoxine prophylaxis recommended in isoniazid-treated individuals with nutritional deficiency (e.g., meat and milk-deficient diet), diabetes mellitus, HIV infection, renal failure, alcoholism, and in exclusively breast-fed infants, pregnant women, and lactating women.c d
Also has been used to prevent or treat neurotoxic adverse effects (e.g., peripheral neuropathy) associated with ethionamide or capecitabine.a b
Adjunct for treatment of acute toxicity resulting from isoniazid overdosage.a b
Adjunct for treatment of acute toxicity caused by mushrooms† of the genus Gyromitra.153 154 155 Used to correct marked neurologic effects (e.g., seizures, coma) induced by methylhydrazine (produced by hydrolysis of the toxins in these mushrooms).153 154 155
Pyridoxine Hydrochloride Dosage and Administration
Usually administered orally.a May be administered by IM, IV, or sub-Q injection when oral administration is not feasible.a b
Available as pyridoxine hydrochloride; dosage expressed in terms of pyridoxine hydrochloride.a b
Dietary and Replacement Requirements
Infants ≤6 months of age: Recommended AI is 0.1 mg (0.01 mg/kg) daily.157
Infants 7–12 months of age: Recommended AI is 0.3 mg (0.03 mg/kg) daily.157
Children 1–3 years of age: RDA is 0.5 mg daily.157
Children 4–8 years of age: RDA is 0.6 mg daily.157
Children 9–13 years of age: RDA is 1 mg of daily.157
Boys 14–18 years of age: RDA is 1.3 mg daily.157
Girls 14–18 years of age: RDA is 1.2 mg daily.157
Maintenance following parenteral administration: 2–100 mg daily has been recommended.a
IM or IV
10–100 mg has been recommended.a Follow with lifelong oral pyridoxine.a
2.5–10 mg daily.a
After clinical signs of deficiency are corrected, administer a multivitamin preparation containing 2–5 mg of pyridoxine hydrochloride once daily for several weeks.a
IM or IV
10–20 mg daily for 3 weeks.b
Follow with a multivitamin preparation containing 2–5 mg of pyridoxine hydrochloride once daily for several weeks.b
Dietary and Replacement Requirements
Men and women 19–50 years of age: RDA is 1.3 mg daily.157
Men ≥51 years of age: RDA is 1.7 mg daily.157
Women ≥51 years of age: RDA is 1.5 mg daily.157
Prevention of Drug-induced Neurotoxicity
CDC recommends 25 mg daily for certain isoniazid-treated patients.c
IV followed by IM
Ingestion of >10 g of isoniazid: Dose of pyridoxine hydrochloride equals the amount of isoniazid ingested.b
Initially, 4 g IV; followed by 1 g IM every 30 minutes until the entire dose has been given.b
25 mg/kg infused over 15–30 minutes and repeated as necessary to control effects up to a maximum cumulative dose of 15–20 g daily has been suggested.153 154 155
Long-term (> 2 months) administration of large dosages (≥ 2 g daily) can cause sensory neuropathy or neuronopathy syndromes.115 120 123
RDA for pregnant women is 1.9 mg daily.157
RDA for lactating women is 2 mg daily.157 Requirements increased in lactating women to ensure adequate concentration of the vitamin in milk (130 ng/mL).157
Cautions for Pyridoxine Hydrochloride
Known sensitivity to pyridoxine or any ingredient in the formulation.b
According to one manufacturer, pyridoxine should not be administered IV to patients with heart disease.a
Some pyridoxine hydrochloride injection preparations contain aluminum that may be toxic.b Aluminum may reach toxic levels with prolonged parenteral administration if kidney function is impaired.b Premature neonates are particularly at risk because their kidneys are immature, and they require large amounts of calcium and phosphate solutions, which contain aluminum.b
Research indicates that patients with impaired kidney function, including premature neonates, who receive parenteral levels of aluminum >4–5 mcg/kg daily accumulate aluminum at levels associated with CNS and bone toxicity.b Tissue loading may occur at even lower rates of administration.b
Distributed into milk.157 Caution if parenteral preparation is used in nursing women.b
Parenteral preparation: Safety and efficacy not established.b
Common Adverse Effects
Usually nontoxic; adverse neurologic effects, nausea, headache, paresthesia, somnolence, increased serum AST, decreased serum folic acid concentrations.a
Interactions for Pyridoxine Hydrochloride
For information regarding isoniazid, see Prevention or Treatment of Drug-induced Neurotoxicity under Uses and Prevention of Drug-induced Neurotoxicity and Isoniazid Overdosage under Dosage and Administration.
Specific Drugs and Laboratory Tests
Anticonvulsants (phenobarbital, phenytoin)
Decreased plasma concentrations of the anticonvulsanta
Pyridoxine interferes with therapeutic effect of levodopaa
Interaction does not occur with levodopa/carbidopaa
Test for urobilinogen using Ehrlich's reagent
Possible false-positive resulta
Pyridoxine Hydrochloride Pharmacokinetics
Readily absorbed from the GI tract.a
Stored mainly in liver with lesser amounts in muscle and brain.157
Crosses the placenta; plasma concentrations in the fetus 5 times greater than maternal plasma concentrations.a Distributed into milk.157
Plasma Protein Binding
Highly protein bound.a
Metabolized to 4-pyridoxic acid in the liver.b
Metabolite excreted in urine.b
Well-closed container at <40°C ; maintain at 15–30°C.a Protect from light.a
20–25°C. b Protect from light.b
An exogenous source of vitamin B6 is required for amino acid, carbohydrate, and lipid metabolism.a b
Natural substances with vitamin B6 activity are pyridoxine in plants and pyridoxal and pyridoxamine in animals.b
Pyridoxamine phosphate and pyridoxal phosphate are active forms of the vitamin.b
Advice to Patients
Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs as well as concomitant illness.a
Importance of proper dietary habits, including taking appropriate AI or RDA of vitamin B6.a
Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.a
Importance of informing patients of other important precautionary information.a (See Cautions.)
Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.
Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.
* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name
Pyridoxine hydrochloride also is commercially available in combination with other vitamins, minerals, amino acids, infant formulas, and protein supplements. For IV infusion, pyridoxine hydrochloride is also commercially available in combination with other vitamins in caloric and electrolyte solutions.a
AHFS DI Essentials. © Copyright 2018, Selected Revisions September 1, 2007. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.
115. Schaumburg H, Kaplan J, Windebank A et al. Sensory neuropathy from pyridoxine abuse: a new megavitamin syndrome. N Engl J Med. 1983; 309:445-8. [PubMed 6308447]
116. Wilcken DEL, Wilcken B, Dudman NPB et al. Homocystinuria—the effects of betaine in the treatment of patients not responsive to pyridoxine. N Engl J Med. 1983; 309:448-53. [PubMed 6877313]
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127. Abraham GE. Nutritional factors in the etiology of the premenstrual tension syndromes. J Reprod Med. 1983; 28:446-64. [PubMed 6684167]
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156. National Research Council Food and Nutrition Board Subcommittee on the Tenth Edition of the RDAs. Recommended dietary allowances. 10th ed. Washington, DC: National Academy Press; 1989:142-50.
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b. Abraxis Pharmaceuticals. Pyridoxine Hydrochloride injection prescribing information. Schaumburg, IL; 2005 Jun.
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