Pyridoxine (Vitamin B6)

What other names is Vitamin B6 known by?

Adermine Chlorhydrate, Adermine Hydrochloride, B Complex Vitamin, B6, Chlorhydrate de pyridoxine, Complexe de Vitamines B, Phosphate de Pyridoxal, Phosphate de Pyridoxamine, Piridoxina, Pyridoxal, Pyridoxal Phosphate, Pyridoxal 5 Phosphate, Pyridoxal-5-Phosphate, Pyridoxal-5'-Phosphate, Pyridoxamine, Pyridoxamine Phosphate, Pyridoxamine-5'-Phosphate, Pyridoxine, Pyridoxine HCl, Pyridoxine Hydrochloride, Pyridoxine-5-Phosphate, Pyridoxine-5'-Phosphate, P5P, P-5-P, Vitamin B-6, Vitamina B6, Vitamine B6.

What is Vitamin B6?

Vitamin B6 is a type of B vitamin. It can be found in certain foods such as cereals, beans, vegetables, liver, meat, and eggs. It can also be made in a laboratory.

Vitamin B6 is used for preventing and treating low levels of pyridoxine (pyridoxine deficiency) and the "tired blood" (anemia) that may result. It is also used for heart and blood vessel disease; high cholesterol and other fats in the blood; high blood pressure; stroke; reducing blood levels of homocysteine, a chemical that might be linked to heart disease; and helping clogged arteries stay open after a balloon procedure to unblock them (angioplasty).

Women use vitamin B6 for premenstrual syndrome (PMS) and other menstruation problems, "morning sickness" (nausea and vomiting) in early pregnancy, stopping breastmilk flow after childbirth, depression related to pregnancy, menopause, or using birth control pills, and symptoms of menopause.

Vitamin B6 is also used for Alzheimer's disease and other types of dementia or memory loss, attention deficit-hyperactivity disorder (ADHD), Down syndrome, autism, diabetes and related nerve pain, sickle cell anemia, migraine headaches, asthma, carpal tunnel syndrome, night leg cramps, muscle cramps, arthritis, preventing fractures in people with weak bones, allergies, acne and various other skin conditions, and infertility. It is also used for dizziness, motion sickness, preventing the eye disease age-related macular degeneration (AMD), seizures, convulsions due to fever, and movement disorders (tardive dyskinesia, hyperkinesis, chorea), as well as for increasing appetite and helping people remember dreams.

Some people use vitamin B6 for boosting the immune system, eye infections, bladder infections, tooth decay, and preventing polyps, cancer, and kidney stones.

Vitamin B6 is also used to overcome certain harmful side effects related to radiation treatment and treatment with medications such as mitomycin, procarbazine, cycloserine, fluorouracil, hydrazine, isoniazid, penicillamine, and vincristine.

Vitamin B6 is also used for nausea and vomiting associated with gastrointestinal illness in children and with use of birth control taken by mouth.

Vitamin B6 is frequently used in combination with other B vitamins in vitamin B complex products.

You may remember a prescription medication called Bendectin that was used for morning sickness in pregnancy. Bendectin contained vitamin B6 (pyridoxine) and a sleep-inducing antihistamine called doxylamine. The makers of Bendectin took it off the market in 1983 because they were running up expensive legal bills in defense of their product. Opponents charged it might be responsible for birth defects. Meanwhile, a product called Diclectin that is similar to Bendectin remained available in Canada, and there was research showing that neither vitamin B6 (pyridoxine) nor Bendectin seems to cause birth defects in animals. After Bendectin was removed from the market, there was no reduction in birth defects, but hospitalization rates for pregnancy-related nausea and vomiting doubled.



Effective for...

  • Anemia (sideroblastic anemia). Taking vitamin B6 by mouth is effective for treating an inherited type of anemia called sideroblastic anemia.
  • Certain seizures in infants (pyridoxine-dependent seizures). Administering vitamin B6 as pyridoxine intravenously (by IV) controls seizures in infants that are caused by pyridoxine dependence.
  • Vitamin B6 deficiency. Taking vitamin B6 by mouth is effective for preventing and treating vitamin B6 deficiency.

Likely Effective for...

  • High homocysteine blood levels. Taking vitamin B6 as pyridoxine by mouth alone or together with folic acid is effective for treating high homocysteine levels in the blood.

Possibly Effective for...

  • Age-related vision loss (macular degeneration). Some research shows that taking vitamin B6 as pyridoxine with other vitamins including folic acid and vitamin B12 might help prevent the loss of vision caused by the eye disease called macular degeneration.
  • Hardening of the arteries (atherosclerosis). As people age, their arteries tend to lose their ability to stretch and flex. Garlic and other ingredients seem to reduce this effect. Taking a specific supplement containing garlic, amino acids (part of proteins), and vitamins such as folic acid, vitamin B12, and vitamin B6 (Kyolic, Total Heart Health, Formula 108, Wakunga) seem to reduce symptoms of hardening of the arteries.
  • Kidney stones. People with a hereditary disorder called type I primary hyperoxaluria have an increased risk of forming kidney stones. There is some evidence that taking vitamin B6 by mouth, alone or along with magnesium, or getting vitamin B6 injected into the vein, can decrease the risk of kidney stones in people with this condition. However, it does not appear to help people with other kinds of kidney stones.
  • Upset stomach and vomiting in pregnancy. Some research suggests that taking vitamin B6, usually as pyridoxine, improves symptoms of mild to moderate nausea and vomiting during pregnancy. The American College of Obstetrics and Gynecology considers vitamin B6 as pyridoxine a first-line treatment for nausea and vomiting caused by pregnancy. Vitamin B6 (pyridoxine) plus the medication doxylamine is recommended for women who do not get better when treated with just vitamin B6 (pyridoxine). However, taking this combination is less effective than the medication ondansetron.
  • Premenstrual syndrome (PMS). There is some evidence that taking vitamin B6 as pyridoxine by mouth can improve PMS symptoms including breast pain. The lowest effective dose should be used. Higher doses will increase the chance of side effects and are not likely to increase the beneficial effects.
  • Movement disorders (tardive dyskinesia).Taking vitamin B6 seems to improve movement disorders in people taking certain drugs for schizophrenia.

Possibly Ineffective for...

  • Memory and thinking skills in older people. One study shows that taking vitamin B6, folic acid, and vitamin B12 might help prevent certain parts of the brain from deteriorating in elderly people. However, most research shows that taking vitamin B6 along with folic acid and vitamin B12 does not improve mental function in elderly people.
  • Alzheimer's disease. Early research suggests that higher intake of vitamin B6 from supplements or as part of the diet is not associated with a reduced risk of Alzheimer's disease in older people.
  • Autism. Taking vitamin B6 as pyridoxine along with magnesium does not seem to improve autistic behavior in children.
  • Carpal tunnel syndrome. Although some early research suggests that taking vitamin B6 as pyridoxine might relieve certain symptoms of carpal tunnel syndrome, most research suggests that this supplement does not benefit people with this condition.
  • Side effects of cancer treatment. One study shows that taking vitamin B6 as pyridoxine at a high dose of 400 mg per day reduces the risk of hand-foot syndrome in chemotherapy patients by 45% compared to taking 200 mg per day. However, most research suggests that taking vitamin B6 as pyridoxine does not reduce symptoms called hand-foot syndrome.
  • Colorectal polyps. Research suggests that taking a combination of folic acid, vitamin B6, and vitamin B12 does not reduce the risk of colorectal polyps in women at high risk of heart disease.
  • Weak bones (osteoporosis). Research suggests taking a combination of folic acid, vitamin B6, and vitamin B12 does not prevent broken bones in people with weak bones and conditions that disrupt blood flow to the brain.

Insufficient Evidence to Rate Effectiveness for...

  • Acne. Early research suggests that taking a specific product (NicAzel, Elorac Inc., Vernon Hills, IL), containing nicotinamide, azelaic acid, zinc, vitamin B6, copper, and folic acid, reduces lesion swelling and helps with the appearance of acne in adults and children.
  • Preventing re-blockage of blood vessels after angioplasty. Evidence on the benefits of vitamin B6 for preventing the re-blockage of blood vessels after angioplasty is inconsistent. Some evidence suggests that taking folic acid, vitamin B12, and vitamin B6 might reduce the re-blockage of blood vessels in people treated with balloon angioplasty. But other research shows no benefit in people who underwent coronary stenting.
  • Asthma. The effectiveness of vitamin B6 supplementation in children with asthma is unclear.
  • Itchy and inflamed skin (atopic dermatitis (eczema)). Early research suggests that taking vitamin B6 as pyridoxine daily for 4 weeks does not reduce eczema symptoms in children.
  • Attention deficit-hyperactivity disorder (ADHD). Early research suggests that taking vitamin B6 by mouth, with or without high doses of other B vitamins, might help ADHD. However, research using high doses of both vitamin B6 and vitamins seems to have no effect on ADHD symptoms.
  • Cancer. Early research suggests that taking a combination of fatty acids commonly found in fish oil (EPA and DHA) along with B vitamins, such as vitamin B12, vitamin B6, and folic acid, does not reduce the risk of getting any type of cancer in people with heart disease.
  • Heart disease. Analysis of data from a clinical trial suggests that taking vitamin B6, folic acid, and vitamin B12 reduces the risk of death due to blood vessel problems in people with a history of stroke or mini stroke who are not taking blood thinners. But it doesn't seem to reduce the risk of heart attack. Also, it doesn't appear to reduce the risk of death due to blood vessel problems in people already taking blood thinners.
  • Side effects of birth control pills (oral contraceptives). Early research suggests that taking vitamin B6 might reduce the risk of side effects due to birth control. Vitamin B6 might reduce the risk of nausea/lack of appetite, headache, and depression in people taking birth control.
  • High blood sugar during pregnancy (gestational diabetes). Early research suggests that taking vitamin B6 for two weeks improves blood sugar levels in people with gestational diabetes and low levels of vitamin B6. However, other research shows no benefit.
  • Nerve pain in people with diabetes. There is conflicting evidence about the role of vitamin B6 in people with diabetes-related nerve pain (diabetic neuropathy). Some research suggests that taking vitamin B6 (pyridoxine) with thiamine or folic acid and vitamin B12 improves some symptoms of nerve pain so that people feel happier. However, the nerves do not seem to function any better.
  • Painful periods (dysmenorrhea). Early research suggests that taking vitamin B6 daily might reduce painful periods.
  • Behavior disorder in children caused by low serotonin levels (hyperkinetic cerebral dysfunction syndrome). Early research shows that taking high doses of vitamin B6 by mouth might have a beneficial effect on children with a behavior disorder caused by low serotonin levels.
  • High blood pressure. Early research suggests that taking pyridoxine can lower blood pressure in people with high blood pressure.
  • High levels of fat in the blood (hypertriglyceridemia). Early research suggests that taking vitamin B6 does not reduce high levels of blood fats called triglycerides. However, it might slightly reduce cholesterol levels.
  • Nerve damage caused by tuberculosis medication. Early research suggests that taking vitamin B6 daily might reduce nerve damage caused by a drug taken for tuberculosis.
  • Stopping breast milk production. Early research suggests that taking vitamin B6 daily for about one week does not stop breast milk production.
  • Lung cancer. Male smokers who have higher blood levels of vitamin B6 seem to have a lower risk of lung cancer. It's not clear if taking supplements reduces the risk of lung cancer.
  • Nausea and vomiting. Early research suggests that taking vitamin B6 does not reduce nausea or vomiting or improve symptoms of dehydration in children with an infection in the stomach or intestines.
  • Complications in pregnancy. Taking vitamin B6 during pregnancy does not seem to reduce the risk of eclampsia, pre-eclampsia, or preterm birth. However, it may reduce the risk of tooth decay.
  • Seizures caused by a high fever. Early research suggests that taking vitamin B6 daily for 12 months does not reduce the recurrence of seizures caused by a high fever in children.
  • Stroke. There is conflicting evidence about the role of vitamin B6 in people with a history of stroke. Taking vitamin B6 along with other B vitamins by mouth does not seem to prevent the occurrence of another stoke in most people with a history of stroke or mini-stroke. However, it might reduce the risk of having another stroke in people with a history of stroke who are not using blood thinner medications.
  • Nerve damage caused by chemotherapy. One report suggests that vitamin B6 might help reverse nerve damage caused by the chemotherapy drug vincristine. Research is needed to confirm these results.
  • Allergies.
  • Arthritis.
  • Boosting the immune system.
  • Eye problems.
  • Kidney problems.
  • Lyme disease.
  • Muscle cramps.
  • Night leg cramps.
  • Other conditions.
More evidence is needed to rate vitamin B6 for these uses.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).

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How does Vitamin B6 work?

Vitamin B6 is required for the proper function of sugars, fats, and proteins in the body. It is also required for the proper growth and development of the brain, nerves, skin, and many other parts of the body.

Are there safety concerns?

Vitamin B6 is LIKELY SAFE for most people when used appropriately.

Vitamin B6 is POSSIBLY SAFE when taken by mouth in amounts greater than the recommended dietary allowance. In some people, vitamin B6 might cause nausea, vomiting, stomach pain, loss of appetite, headache, tingling, sleepiness, and other side effects.

Long-term use of high doses of vitamin B6 and when vitamin B6 is given as a shot into the muscle is POSSIBLY UNSAFE. When used orally in high doses it might cause certain brain and nerve problems. When given as a shot into the muscle it might cause muscle problems.

Special Precautions & Warnings:

Pregnancy and breast-feeding: Vitamin B6 is LIKELY SAFE for pregnant women when taken under the supervision of their healthcare provider. It is sometimes used in pregnancy to control morning sickness. High doses are UNSAFE. High doses can cause newborns to have seizures.

Vitamin B6 is LIKELY SAFE for breast-feeding women when used in amounts not larger than 2 mg per day (the recommended dietary allowance). Avoid using higher amounts. Not enough is known about the safety of vitamin B6 at higher doses in breast-feeding women.

Procedures to widen narrowed arteries (angioplasty). Using vitamin B6 along with folic acid and vitamin B12 intravenously (by IV) or by mouth might worsen narrowed arteries. Vitamin B6 should not be used by people recovering from this procedure.

Diabetes. Using vitamin B6, folic acid, and vitamin B12 might increase the risk of cancer in people with diabetes and a recent stroke. Vitamin B6 should not be used by patients with diabetes that have had a recent stroke.

Are there any interactions with medications?



Phenytoin (Dilantin)
Interaction Rating: Major Do not take this combination.

The body breaks down phenytoin (Dilantin) to get rid of it. Vitamin B6 might increase how quickly the body breaks down phenytoin. Taking vitamin B6 along with phenytoin (Dilantin) might decrease the effectiveness of phenytoin (Dilantin) and increase the possibility of seizures. Do not take large doses of vitamin B6 if you are taking phenytoin (Dilantin).



Amiodarone (Cordarone)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Amiodarone (Cordarone) might increase your sensitivity to sunlight. Taking vitamin B6 along with amiodarone (Cordarone) might increase the chances of sunburn, blistering, or rashes on areas of skin exposed to sunlight. Be sure to wear sunblock and protective clothing when spending time in the sun.



Medications for high blood pressure (antihypertensive drugs)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Vitamin B6 might lower blood pressure. It has the potential to add to blood pressure-lowering effects of antihypertensive drugs and increase the risk of blood pressure becoming too low.

Some medications used to lower blood pressure include captopril (Capoten), enalapril (Vasotec), losartan (Cozaar), valsartan (Diovan), diltiazem (Cardizem), amlodipine (Norvasc), hydrochlorothiazide (HydroDiuril), furosemide (Lasix), and many others.



Phenobarbital (Luminal)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

The body breaks down phenobarbital (Luminal) to get rid of it. Vitamin B6 might increase how quickly the body breaks down phenobarbital (Luminal). This could decrease the effectiveness of phenobarbital (Luminal).



Levodopa
Interaction Rating: Minor Be cautious with this combination.
Talk with your health provider.

The body breaks down levodopa to get rid of it. Vitamin B6 can increase how quickly the body breaks down and gets rid of levodopa. However, this is only a problem if you are taking levodopa alone. Most people take levodopa along with carbidopa (Sinemet). Carbidopa prevents this interaction from occurring. If you are taking levodopa without carbidopa, do not take vitamin B6.

Dosing considerations for Vitamin B6.

The following doses have been studied in scientific research:

ADULTS

BY MOUTH:
  • For hereditary sideroblastic anemia: Initially, 200-600 mg of vitamin B6 is used. The dose is decreased to 30-50 mg per day after an adequate response.
  • For vitamin B6 deficiency: In most adults, the typical dose is 2.5-25 mg daily for three weeks then 1.5-2.5 mg per day thereafter. In women taking birth control pills, the dose is 25-30 mg per day.
  • For abnormally high levels of homocysteine in the blood: For reducing high levels of homocysteine in the blood after childbirth, 50-200 mg of vitamin B6 has been taken alone. Also, 100 mg of vitamin B6 has been taken in combination with 0.5 mg of folic acid.
  • For preventing macular degeneration: 50 mg of vitamin B6 in the form of pyridoxine has been used daily in combination with 1000 mcg of vitamin B12 (cyanocobalamin) 1000 mcg and 2500 mcg of folic acid for about 7 years.
  • For hardening of the arteries (atherosclerosis): A specific supplement (Kyolic, Total Heart Health, Formula 108, Wakunga) containing 250 mg of aged garlic extract, 100 mcg of vitamin B12, 300 mcg of folic acid, 12.5 mg of vitamin B6, and 100 mg of L-arginine daily for 12 months.
  • For kidney stones: 25-500 mg of vitamin B6 has been used daily.
  • For nausea during pregnancy: 10-25 mg of vitamin B6 taken three or four times per day has been used. In people who don't respond to vitamin B6 alone, a combination product containing vitamin B6 and the drug doxylamine (Diclectin, Duchesnay Inc.) is used three or four times per day. Also, another product containing 75 mg of vitamin B6, 12 mcg of vitamin B12, 1 mg of folic acid, and 200 mg of calcium (PremesisRx, KV Pharmaceuticals) is used daily.
  • For symptoms of premenstrual syndrome (PMS): 50-100 mg of vitamin B6 is used daily, alone or along with 200 mg of magnesium.
  • For treating tardive dyskinesia: 100 mg of vitamin B6 per day has been increased weekly up to 400 mg per day, given in two divided doses.
INJECTED INTO THE MUSCLE:
  • Hereditary sideroblastic anemia: 250 mg of vitamin B6 daily, reduced to 250 mg of vitamin B6 weekly once adequate response is achieved.
CHILDREN

BY MOUTH:
  • For kidney stones: Up to 20 mg/kg daily in children aged 5 years and up.
INJECTED INTO THE VEIN OR MUSCLE:
  • For seizures that respond to vitamin B6 (pyridoxine-dependent seizures): 10-100 mg is recommended.
The daily recommended dietary allowances (RDAs) of vitamin B6 are: Infants 0-6 months, 0.1 mg; Infants 7-12 months, 0.3 mg; Children 1-3 years, 0.5 mg; Children 4-8 years, 0.6 mg; Children 9-13 years, 1 mg; Males 14-50 years, 1.3 mg; Males over 50 years, 1.7 mg; Females 14-18 years, 1.2 mg; Females 19-50 years, 1.3 mg; Females over 50 years, 1.5 mg; Pregnant women, 1.9 mg; and breast-feeding women, 2 mg. Some researchers think the RDA for women 19-50 years should be increased to 1.5-1.7 mg per day. The recommended maximum daily intake is: Children 1-3 years, 30 mg; Children 4-8 years, 40 mg; Children 9-13 years, 60 mg; Adults, pregnant and breast-feeding women, 14-18 years, 80 mg; and Adults, pregnant and breast-feeding women, over 18 years, 100 mg.

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Last Editorial Review: 3/29/2011

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