From the Guidelines
Medications that interfere with vitamin B6 metabolism include isoniazid, hydralazine, penicillamine, cycloserine, and certain anticonvulsants, while medical conditions such as celiac disease, kidney disease, and liver disease can also impact B6 levels, and supplementation may be necessary, typically 25-100 mg daily, as determined by a healthcare provider based on individual needs and blood levels 1.
Medications Affecting B6 Metabolism
- Isoniazid (used for tuberculosis) can lead to B6 deficiency, particularly in individuals with risk factors such as pregnancy, HIV, or malnutrition, and pyridoxine supplementation is recommended at a dose of 25-50 mg/day 1
- Hydralazine (for hypertension) and penicillamine (for rheumatoid arthritis) can also deplete B6 levels
- Cycloserine, an antibiotic, and certain anticonvulsants like phenytoin, carbamazepine, and phenobarbital can interfere with B6 metabolism
Medical Conditions Affecting B6 Metabolism
- Celiac disease, Crohn's disease, and ulcerative colitis can reduce B6 absorption
- Kidney disease, particularly those requiring dialysis, can lead to B6 deficiency due to impaired activation and increased excretion
- Liver disease impairs the activation of B6 to its active form, pyridoxal 5'-phosphate (PLP)
- Autoimmune conditions and malabsorption syndromes can also impact B6 metabolism
Supplementation and Dosage
- B6 supplementation may be necessary for individuals with conditions or taking medications that interfere with B6 metabolism
- Typical dosing ranges from 25-100 mg daily, but should be determined by a healthcare provider based on individual needs and blood levels 1
- It is essential to monitor blood levels and adjust supplementation accordingly to avoid toxicity and ensure adequate levels for optimal health.
From the FDA Drug Label
Pyridoxine (vitamin B6) deficiency is sometimes observed in adults with high doses of isoniazid and is considered probably due to its competition with pyridoxal phosphate for the enzyme apotryptophanase.
- Medications that can affect B6 metabolism: Isoniazid can affect B6 metabolism by competing with pyridoxal phosphate for the enzyme apotryptophanase, leading to pyridoxine deficiency.
- Conditions that can affect B6 metabolism: Malnutrition, alcoholism, and diabetes may predispose individuals to neuritis and affect B6 metabolism, especially when taking isoniazid 2.
From the Research
Medications Affecting B6 Metabolism
- Isoniazid, a medication used to treat tuberculosis, can affect vitamin B6 metabolism, with reports of neuropathy as an adverse event, which may be related to B6 deficiency 3, 4.
- D-penicillamine, a chelating agent used to treat Wilson's disease, has been linked to a risk of vitamin B6 deficiency, although a study found that long-term stable Wilson's disease patients under D-penicillamine treatment may not need vitamin B6 supplementation 5.
Conditions Affecting B6 Metabolism
- Wilson's disease, a copper metabolism disorder, may require treatment with medications that can affect vitamin B6 metabolism, such as D-penicillamine 5, 6.
- Tuberculosis, particularly when treated with isoniazid, may require monitoring for vitamin B6 deficiency due to the risk of neuropathy and other adverse events 3, 4.