Skip to Content


Class: Vitamin B Complex
VA Class: VT109
Chemical Name: 2-methyl-3-hydroxy-4,5-bis (hydroxymethyl) pyridine hydrochloride
CAS Number: 58-56-0

Medically reviewed by Last updated on Aug 24, 2020.


Water-soluble, B complex vitamin.a

Uses for Pyridoxine

Pyridoxine Deficiency

Treatment of vitamin B6 deficiency.a b

Dietary Requirements

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

Pyridoxine-dependent Seizures

Treatment of pyridoxine-dependent seizures.159 a b

Metabolic Disorders

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

Mushroom Toxicity

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 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

Pediatric Patients

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

Pyridoxine-dependent Seizures

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


Pyridoxine Deficiency

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

Isoniazid Overdose
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

Mushroom Toxicity†

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

Prescribing Limits


Long-term (> 2 months) administration of large dosages (≥ 2 g daily) can cause sensory neuropathy or neuronopathy syndromes.115 120 123

Special Populations

Pregnant Women

RDA for pregnant women is 1.9 mg daily.157

Lactating Women

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


  • 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


General Precautions

Aluminum Content

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

Specific Populations


Category A.b


Distributed into milk.157 Caution if parenteral preparation is used in nursing women.b

Pediatric Use

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

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 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

Elimination Route

Metabolite excreted in urine.b


15-20 days.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


Dosage Forms


Brand Names






10 mg*

25 mg*

50 mg*

100 mg*

200 mg*

250 mg*

500 mg*

Tablets, extended-release

200 mg*



100 mg/mL*

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 2021, Selected Revisions September 1, 2007. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.

† Use is not currently included in the labeling approved by the US Food and Drug Administration.


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.

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.

117. Watson S, Lacouture PG, Lovejoy FH. Single high-dose pyridoxine treatment for isoniazid overdose. JAMA. 1981; 246:1102-4.

120. Schaumburg H. Sensory neuropathy from pyridoxine abuse. N Engl J Med. 1984; 310:197-8.

121. Krinke G, Schaumburg HH, Spencer PS et al. Pyridoxine megavitaminosis produces degeneration of peripheral sensory neurons (sensory neuronopathy) in the dog. Neurotoxicology. 1981; 2:13-24.

122. Berger A, Schaumburg HH. More on neuropathy from pyridoxine abuse. N Engl J Med. 1984; 311:986-7.

123. Vasile A, Goldberg R, Kornberg B. Pyridoxine toxicity: report of a case. J Am Osteopath Assoc. 1984; 83:790-1.

124. Phillips WEJ, Mills JHL, Charbonneau SM et al. Subacute toxicity of pyridoxine hydrochloride in the beagle dog. Toxicol Appl Pharmacol. 1978; 44:323-33.

125. Dalton K. Pyridoxine overdose in premenstrual syndrome. Lancet. 1985; 1:1168-9.

126. Premenstrual syndrome: a report by the American Council on Science and Health. Meister KA, ed. Summit, NJ: American Council on Science and Health; 1985; (Jul):13-5.

127. Abraham GE. Nutritional factors in the etiology of the premenstrual tension syndromes. J Reprod Med. 1983; 28:446-64.

128. Pariser SF, Stern SL, Shank ML et al. Premenstrual syndrome: concerns, controversies, and treatment. Am J Obstet Gynecol. 1985; 153:599-604.

129. Stokes JW, Mendels J. Pyridoxine and premenstrual tension. Lancet. 1972; 1:1177-8.

130. Hagen I, Nesheim BI, Tuntland T. No effect of vitamin B-6 against premenstrual tension: a controlled clinical study. Acta Obstet Gynecol Scand. 1985; 64:667-70.

131. Williams MJ, Harris RI, Dean BC. Controlled trial of pyridoxine in the premenstrual syndrome. J Int Med Res. 1985; 13:174-9.

132. Chakmakjian ZH. A critical assessment of therapy for the premenstrual tension syndrome. J Reprod Med. 1983; 28:532-8.

133. Brush MG, Perry M. Pyridoxine and the premenstrual syndrome. Lancet. 1:1399. Letter.

150. Yendt ER, Cohanim M. Response to a physiologic dose of pyridoxine in type I primary hyperoxaluria. N Engl J Med. 1985; 312:953-7.

151. Harati Y, Niakan E. Hydrazine toxicity, pyridoxine therapy, and peripheral neuropathy. Ann Intern Med. 1986; 104:728-9.

152. de Zegher F, Przyrembel H et al. Successful treatment of infantile type I primary hyperoxaluria complicated by pyridoxine toxicity. Lancet. 1985; 2:392-3.

153. Hanrahan JP, Gordon MA. Mushroom poisoning: case reports and a review of therapy. JAMA. 1984; 251:1057-61.

154. Gosselin RE, Smith RP, Hodge HC. Clinical toxicology of commercial products. 5th ed. Baltimore: Williams & Wilkins; 1984:II-247,III-294-5.

155. George ME, Pinkerton MK, Back KC. Therapeutics of monomethylhydrazine intoxication. Toxicol Appl Pharmacol. 1982; 63:201-8.

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.

157. Standing Committee on the Scientific Evaluation of Dietary Reference Intakes of the Food and Nutrition Board, Institute of Medicine, National Academy of Sciences. Dietary reference intakes for thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid, biotin, and choline. Washington, DC: National Academy Press; 1998. (Prepublication copy uncorrected proofs.)

158. Committee on Infectious Diseases, American Academy of Pediatrics. 1997 Red book: report of the Committee on Infectious Diseases. 24th ed. Elk Grove Village, IL: American Acdemy of Pediatrics; 1997:344-7.

159. Gospe SM. Current perspectives on pyridoxine-dependent seizures. J Pediatr. 1998; 132:919-23.

160. Rimm EB, Willett WC, Hu FB et al. Folate and vitamin B6 from diet and supplements in relation to risk of coronary heart disease among women. JAMA. 1998; 279:359-64.

161. McCully KS. Homocysteine, folate, vitamin B6, and cardiovascular disease. JAMA. 1998; 279:392-3.

162. Centers for Disease Control and Prevention. Prevention and treatment of tuberculosis among patients infected with human immunodeficiency virus: principles of therapy and revised recommendations. MMWR. 1998; 47(No. RR-20):1-58.

163. Berg D. Managing the side effects of chemotherapy for colorectal cancer. Semin Oncol. 1998; 25(Suppl 11):53-9.

164. Oncologic Drugs Advisory Committee Meeting. 56th meeting. Bethesda, MD: Food and Drug Administration; 1998 Mar 19.

165. Schless JM, Allison RF, Inglis RM et al. The use of ethionamide in combined drug regimens in the retreatment of isoniazid-resistant pulmonary tuberculosis. Am Rev Resp Dis. 1965; 91:728-37.

166. Wyeth. Trecator-SC (ethionamide) tablets prescribing information. In: Physicians’ desk reference. 54th ed. Montvale, NJ: Medical Economics Company Inc; 2000:3327-8.

a. AHFS drug information 2007. McEvoy GK, ed. Pyrodoxine. Bethesda, MD: American Society of Health-Systems Pharmacists; 2007: 3624-6.

b. Abraxis Pharmaceuticals. Pyridoxine Hydrochloride injection prescribing information. Schaumburg, IL; 2005 Jun.

c. Centers for Disease Control and Prevention. Treatment of tuberculosis, American Thoracic Society, CDC, and Infectious Diseases Society of America. MMWR Morb Mortal Wkly Rep. 2003; 52(No. RR-11):1-77.

d. American Academy of Pediatrics. 2006 Red Book: Report of the Committee on Infectious Diseases. 27th ed. Elk Grove Village, IL: American Academy of Pediatrics; 2006.