Vitamin B6 (Pyridoxine): Pharmacological Properties, Clinical Applications, and Nutritional Implications
Abstract
Background: Vitamin B6 (pyridoxine) is a water-soluble vitamin essential for human physiology, primarily through its active coenzyme form, pyridoxal 5-phosphate (PLP). PLP is a crucial cofactor for over 100 enzymes involved in amino acid, carbohydrate, and lipid metabolism, neurotransmitter synthesis, and homocysteine regulation. Deficiency can arise from poor diet, malabsorption, chronic alcoholism, renal disease, and interactions with medications like isoniazid and certain antiepileptics.
Aim: This review aims to consolidate the pharmacological properties, clinical applications, and nutritional implications of vitamin B6, detailing its mechanisms, indications, administration, safety, and the importance of interprofessional management.
Methods: A comprehensive narrative review was conducted, synthesizing information on vitamin B6's biochemistry, pharmacokinetics, therapeutic uses, and toxicity from available literature.
Results: Vitamin B6 has well-defined roles in treating nutritional deficiencies and specific dependency syndromes (e.g., pyridoxine-dependent epilepsy), and as an antidote in isoniazid overdose. It is FDA-approved in a combination product for nausea in pregnancy. However, evidence for its efficacy in other conditions like premenstrual syndrome or carpal tunnel syndrome is inconsistent. While safe at recommended doses, chronic high-dose intake (>1g/day) can cause a dose-dependent, often reversible sensory neuropathy.
Conclusion: Vitamin B6 is fundamental to numerous metabolic processes. Its clinical use ranges from unequivocal indications for deficiency and specific genetic disorders to more empirical applications. Careful dose management and interprofessional collaboration are essential to maximize therapeutic benefits and minimize the risk of neurotoxicity from excessive intake.
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References
SNELL EE. Chemical structure in relation to biological activities of vitamin B6. Vitamins and hormones. 1958:16():77-125
RABINOWITZ JC, SNELL EE. The vitamin B6 group; microbiological and natural occurrence of pyridoxamine phosphate. The Journal of biological chemistry. 1947 Aug:169(3):643-50
SNELL EE. Summary of known metabolic functions of nicotinic acid, riboflavin and vitamin B6. Physiological reviews. 1953 Oct:33(4):509-24
Ebadi M. Regulation and function of pyridoxal phosphate in CNS. Neurochemistry international. 1981:3(3-4):181-205
Wibowo N, Purwosunu Y, Sekizawa A, Farina A, Tambunan V, Bardosono S. Vitamin B₆ supplementation in pregnant women with nausea and vomiting. International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics. 2012 Mar:116(3):206-10. doi: 10.1016/j.ijgo.2011.09.030.
Matthews A, Haas DM, O'Mathúna DP, Dowswell T, Doyle M. Interventions for nausea and vomiting in early pregnancy. The Cochrane database of systematic reviews. 2014 Mar 21:(3):CD007575. doi: 10.1002/14651858.CD007575.pub3.
Snider DE Jr. Pyridoxine supplementation during isoniazid therapy. Tubercle. 1980 Dec:61(4):191-6
Raskin NH, Fishman RA. Pyridoxine-deficiency neuropathy due to hydralazine. The New England journal of medicine. 1965 Nov 25:273(22):1182-5
Nair S, Maguire W, Baron H, Imbruce R. The effect of cycloserine on pyridoxine-dependent metabolism in tuberculosis. Journal of clinical pharmacology. 1976 Aug-Sep:16(8-9):439-43
Clayton PT. B6-responsive disorders: a model of vitamin dependency. Journal of inherited metabolic disease. 2006 Apr-Jun:29(2-3):317-26
Apeland T, Frøyland ES, Kristensen O, Strandjord RE, Mansoor MA. Drug-induced pertubation of the aminothiol redox-status in patients with epilepsy: improvement by B-vitamins. Epilepsy research. 2008 Nov:82(1):1-6. doi: 10.1016/j.eplepsyres.2008.06.003.
MUELLER JF, VILTER RW. Pyridoxine deficiency in human beings induced with desoxypyridoxine. The Journal of clinical investigation. 1950 Feb:29(2):193-201
Hawkins WW, Barsky J. An Experiment on Human Vitamin B6 Deprivation. Science (New York, N.Y.). 1948 Sep 10:108(2802):284-6
Riikonen R, Mankinen K, Gaily E. Long-term outcome in pyridoxine-responsive infantile epilepsy. European journal of paediatric neurology : EJPN : official journal of the European Paediatric Neurology Society. 2015 Nov:19(6):647-51. doi: 10.1016/j.ejpn.2015.08.001.
Frimpter GW, Andelman RJ, George WF. Vitamin B6-dependency syndromes. New horizons in nutrition. The American journal of clinical nutrition. 1969 Jun:22(6):794-805
Lheureux P, Penaloza A, Gris M. Pyridoxine in clinical toxicology: a review. European journal of emergency medicine : official journal of the European Society for Emergency Medicine. 2005 Apr:12(2):78-85
Bender DA. Non-nutritional uses of vitamin B6. The British journal of nutrition. 1999 Jan:81(1):7-20
Salam RA, Zuberi NF, Bhutta ZA. Pyridoxine (vitamin B6) supplementation during pregnancy or labour for maternal and neonatal outcomes. The Cochrane database of systematic reviews. 2015 Jun 3:2015(6):CD000179. doi: 10.1002/14651858.CD000179.pub3.
Bendich A, Cohen M. Vitamin B6 safety issues. Annals of the New York Academy of Sciences. 1990:585():321-30
Larsson SC, Orsini N, Wolk A. Vitamin B6 and risk of colorectal cancer: a meta-analysis of prospective studies. JAMA. 2010 Mar 17:303(11):1077-83. doi: 10.1001/jama.2010.263.
Tryfiates GP. Effects of pyridoxine on serum protein expression in hepatoma-bearing rats. Journal of the National Cancer Institute. 1981 Feb:66(2):339-44
Hayashi H, Wada H, Yoshimura T, Esaki N, Soda K. Recent topics in pyridoxal 5'-phosphate enzyme studies. Annual review of biochemistry. 1990:59():87-110
Hamm MW, Mehansho H, Henderson LM. Transport and metabolism of pyridoxamine and pyridoxamine phosphate in the small intestine of the rat. The Journal of nutrition. 1979 Sep:109(9):1552-9
Buss DD, Hamm MW, Mehansho H, Henderson LM. Transport and metabolism of pyridoxine in the perfused small intestine and the hind limb of the rat. The Journal of nutrition. 1980 Aug:110(8):1655-63
Tsuji T, Yamada R, Nose Y. Intestinal absorption of vitamin B6. I. Pyridoxol uptake by rat intestinal tissue. Journal of nutritional science and vitaminology. 1973 Oct:19(5):401-17
Mehansho H, Buss DD, Hamm MW, Henderson LM. Transport and metabolism of pyridoxine in rat liver. Biochimica et biophysica acta. 1980 Aug 1:631(1):112-23
Mehansho H, Henderson LM. Transport and accumulation of pyridoxine and pyridoxal by erythrocytes. The Journal of biological chemistry. 1980 Dec 25:255(24):11901-7
Li TK, Lumeng L, Veitch RL. Regulation of pyridoxal 5'-phosphate metabolism in liver. Biochemical and biophysical research communications. 1974 Nov 27:61(2):677-84
. Sensory neuropathy from pyridoxine abuse. The New England journal of medicine. 1984 Jan 19:310(3):197-8
Ink SL, Henderson LM. Vitamin B6 metabolism. Annual review of nutrition. 1984:4():455-70
Ueland PM, Ulvik A, Rios-Avila L, Midttun Ø, Gregory JF. Direct and Functional Biomarkers of Vitamin B6 Status. Annual review of nutrition. 2015:35():33-70. doi: 10.1146/annurev-nutr-071714-034330.
Tsutsumi S, Tanaka T, Gotoh K, Akaike M. Effects of pyridoxine on male fertility. The Journal of toxicological sciences. 1995 Aug:20(3):351-65
Authors
Copyright (c) 2025 Faris Hulayyil Mohammed Alotaibi, Tariq Mohammed Hadi Marwani, Abdullah Mohammed Hadi Marwani, Khudhayr Abdulrhman Alanazi, Atheer Yahya Alharthi, Layla Yousef Ahmad Albatyan, Khalil Naji Almutairi, Abdulaziz Ibraheem Alrasheed, Abdulaziz Mohammed Yahya Moafa, Sultanah Mohammed Jaber Aljaber
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