Generic Name: pyridoxine

Brand and Other Names: vitamin B6, Nestrex

Drug Class: B Vitamins; Vitamins, Water-Soluble

What is pyridoxine, and what is it used for?

Pyridoxine is a form of vitamin B6, a water-soluble vitamin and an important micronutrient required for the normal functioning of many biological systems in the body.

Pyridoxine is not synthesized naturally in humans and people must obtain it from dietary intake. Pyridoxine is used as a supplement to compensate for natural deficiency and to treat nausea and vomiting in pregnancy. Pyridoxine is also used to prevent or reduce nerve damage associated with isoniazid, a drug used to treat tuberculosis, and poisoning from certain toxic substances.

Pyridoxine is essential for maintaining the health and normal functioning of nerves, muscles, skin and immune function. Pyridoxine is converted to its active form pyridoxal 5-phosphate in the body, a coenzyme involved in the metabolism of proteins, carbohydrates and fats and release of glycogen stored in the liver and muscles. Pyridoxine plays a role in the synthesis of DNA, RNA, neurotransmitters, amino acids including homocysteine, and heme, the molecule in red blood cells that carries oxygen.

Pyridoxine is naturally available in foods such as chickpeas, fish, beef liver and other organ meats, poultry, and many vegetables, seeds and fruits (other than citrus). Deficiency of  pyridoxine can lead to nerve damage (neuropathy), confusion, insomnia and dermatitis. Most healthy people can obtain adequate pyridoxine through dietary intake.

Pyridoxine is available on prescription and over-the-counter and is taken as a supplement by people with natural deficiency or when supplementation is required because of certain conditions or when taking certain drugs. Uses of pyridoxine include:

• Pyridoxine deficiency
• Nausea and vomiting of pregnancy
• Prevention of peripheral neuropathy associated with isoniazid therapy for treatment of Mycobacterium tuberculosis infection
• Prevention and treatment of neurological toxicities including seizures or coma associated with isoniazid overdose
• Ethylene glycol poisoning
• Treatment and prevention of gyromitrin-containing mushroom (false morel) overdose or toxicity
• Hydrazine toxicity

Warnings

• Do not take pyridoxine if you are hypersensitive to pyridoxine or any of the components in the formulation.
• Large doses taken for prolonged periods can cause severe and permanent neuropathies.
• Some intravenous formulations may contain aluminum. Use with caution in premature newborns and patients with impaired kidney function.
• Doses higher than 200 mg may cause dependence and withdrawal.
• Single vitamin deficiency is rare. Evaluate patients with pyridoxine deficiency for other vitamin deficiencies.

What are the side effects of pyridoxine?

Common side effects of pyridoxine include:

• Headache
• Drowsiness (somnolence)
• Abnormal skin sensations (paresthesia)
• Nerve damage (neuropathy)
• Impaired coordination, balance and speech (ataxia)
• Seizure (from very large IV dose)
• Folate deficiency
• Excessive acidity in body fluids (acidosis)
• Increase in liver enzyme AST
• Nausea
• Hypersensitivity reaction

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug.

Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.

What are the dosages of pyridoxine?

Tablets

• 25mg
• 50mg
• 100mg
• 250mg
• 500mg

Tablets, Extended Release

• 200mg

Capsule

• 250mg

Adult:

Recommended Daily Allowance (RDA)

Males

• Younger than 50 years old: 1.3 mg/day
• Older than 50 years old: 1.7 mg/day

Females

• Younger than 50 years old: 1.3 mg/day
• Older than 50 years old: 1.5 mg/day
• Pregnant: 1.9 mg/day
• Lactation: 2 mg

Pyridoxine Deficiency

• 10-20 mg/day intravenous/intramuscular (IV/IM) for 3 weeks
• 2.5-10 mg/day oral

Nausea and Vomiting in Pregnancy

• 10-25 mg orally every 8 hours

Prevention of Peripheral Neuropathy

• Patients treated with isoniazid for Mycobacterium tuberculosis: 25-50 mg/day oral

Pediatric:

RDA

• Children younger than 6 months: 0.1 mg/day
• Children 6-12 months: 0.3 mg/day
• Children 1-3 years: 0.5 mg/day
• Children 3-8 years: 0.6 mg/day
• Children 8-13 years: 1 mg/day
• Children 13-18 years: 1.3 mg/day (male); 1.5 mg/day (female)

Isoniazid-Induced Seizures/Coma

• Dose of pyridoxine is equal to amount of isoniazid ingested
• Administer at rate of 0.5-1 g/min until seizures stop or maximum initial dose (70 mg/kg) administered; may administer every 5-10 minutes as needed to control persistent seizure activity and/or central nervous system (CNS) toxicity

Overdose

• Pyridoxine overdose can neurological symptoms such as tingling and numbness of the extremities, and in severe overdose, difficulty with walking and coordination. There is no specific antidote for pyridoxine toxicity.
• Overdose is treated with discontinuation of pyridoxine supplementation and symptomatic and supportive care until symptoms resolve, including physical therapy.

What drugs interact with pyridoxine?

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

• Pyridoxine has no known severe interactions with other drugs.
• Serious Interactions of pyridoxine include:
  • selinexor
• Moderate Interactions of pyridoxine include:
  • azithromycin
  • cisplatin
  • clarithromycin
  • dichlorphenamide
  • erythromycin base
  • erythromycin ethylsuccinate
  • erythromycin lactobionate
  • erythromycin stearate
  • levodopa
  • omadacycline
  • roxithromycin
• Pyridoxine has mild interactions with at least 71 different drugs.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

Pregnancy and breastfeeding

• Pyridoxine is an essential micronutrient and requirement may go up during pregnancy.
• Pyridoxine is recommended for the treatment of nausea and vomiting of pregnancy.
• Studies show no evidence of fetal farm from pyridoxine use in pregnancy and may offer some protection from congenital cardiovascular malformations in the fetus.
• Pyridoxine use in pregnancy is generally safe in recommended doses.
• Pyridoxine is present in breast milk and is a beneficial nutrient to the breastfeeding baby. Pyridoxine requirement goes up in nursing mothers and is safe if taken by the mother in recommended doses.

What else should I know about pyridoxine?

• Do not take supplemental pyridoxine unless there is deficiency or specific requirement. The best way to meet daily requirement is to eat foods rich in pyridoxine.
• Do not exceed the daily recommended dose if you take over-the-counter pyridoxine supplement.
• In case of overdose, discontinue pyridoxine and seek medical help or contact Poison Control.
• Pyridoxine is marketed as a dietary supplement and is not rigorously regulated by the FDA. There may sometimes be discrepancy between labeling and contents, exercise caution and choose products from reliable manufacturers.