Vitamin B6

Vitamin B6/Drug Interactions:

  • Alzheimer's agentsAlzheimer's agents: Epidemiological studies suggest an association between low blood folate and an increased prevalence of poor test performance in the global cognitive domain and Alzheimer's disease; this result was lacking with vitamin B6 (77; 47).
  • AmiodaroneAmiodarone: According to secondary sources, information is conflicting as to whether pyridoxine exacerbates or protects against amiodarone (Cordarone?)-induced photosensitivity.
  • Antianxiety agentsAntianxiety agents: In clinical research, vitamin B6 in combination with magnesium was effective for significant reductions in premenstrual anxiety (78).
  • AntiasthmaticsAntiasthmatics: Theophylline, a prescription drug used to help manage asthma, has been shown to lower pyridoxine levels (79; 80).
  • AntibioticsAntibiotics: According to secondary sources, destruction of gastrointestinal flora may reduce the production of vitamin B6.
  • Anticoagulants and antiplateletsAnticoagulants and antiplatelets: In a clinical trial, persistent bleeding was reported in one subject (30).
  • AntidepressantsAntidepressants: Preliminary hypotheses suggest that because pyridoxine increases serotonin and GABA levels in the blood, it may benefit people in dysphoric mental states (81). Higher blood levels of homocysteine are associated with increased depression in later life (82); taking pyridoxine supplements in combination with other B vitamins (mainly folic acid) has been shown to be effective for lowering homocysteine levels (6; 7; 8; 9). In human research, a combination of folic acid, vitamin B12, and vitamin B6 was no better than placebo with respect to symptoms of depression in older men (83).
  • AntidiabeticsAntidiabetics: In human research, 100mg of pyridoxine daily improved glucose metabolism in gestational diabetes (32; 33).
  • AntiemeticsAntiemetics: In clinical research, vitamin B6 supplementation had antinausea effects of similar efficiency to ginger in the first trimester of pregnancy (31).
  • AntihypertensivesAntihypertensives: In animal research, vitamin B6 supplementation had hypotensive effects on hypertensive rats (27; 28). In humans, vitamin B6 (5mg/kg daily) reduced the systolic and diastolic blood pressure of hypertensive patients (49).
  • AntineoplasticsAntineoplastics: There are epidemiological data supporting the claim that vitamin B6 lowers the risk of colon cancer (84; 85). Supplementation with a combination of folic acid, vitamin B6, and vitamin B12 lacked an effect on the risk of breast cancer (86). There is evidence that male smokers with higher serum levels of pyridoxine may have a lower risk of lung cancer (87).
  • CycloserineCycloserine: According to review data, cycloserine may affect the metabolism of pyridoxine (88).
  • Cytochrome P450-modifying agentsCytochrome P450-modifying agents: According to secondary sources, vitamin B6 may interact with cytochrome P450 2D6 inhibitors.
  • Dermatologic agentsDermatologic agents: According to secondary sources, acne, allergic reactions, and photosensitivity have been reported. In clinical research, skin rash leading to trial withdrawal was reported with vitamin B6 supplementation (50). In human research on B6 supplementation for atopic eczema, three participants reported eczema flare-up that was caused by bacterial infection (60). A case report of a girl aged 17 years described sudden onset of rosacea fulminans with ingestion of high-dose vitamin B daily; it resolved after discontinuation of the supplement and introduction of a therapeutic regimen of isotretinoin and methylprednisolone (66). According to a systematic review, vitamin B6 lacked an effect on symptoms of eczema based on patient or parent ratings (60).
  • Erythropoietin stimulating agentsErythropoietin stimulating agents: In human research, vitamin B6 status in hemodialysis users was reduced with erythropoietin-stimulating agents and ion exchange phosphate-binding resins; consequently, supplementation is recommended (89).
  • FurosemideFurosemide: In humans, furosemide increased urinary excretion of vitamin B6 (90).
  • GalactagoguesGalactagogues: Clinical studies of pyridoxine used to suppress lactation have yielded mixed results (91; 92). In a meta-analysis, compared to placebo or bromocriptine, treatment with vitamin B6 lacked a statistically significant difference in regard to the failure to attain suppression of lactation at or within seven days after childbirth (50).
  • Homocysteine-lowering agentsHomocysteine-lowering agents: Taking pyridoxine supplements in combination with other B vitamins (mainly folic acid) has been shown to be effective for lowering homocysteine levels (6; 7; 8; 93). However, some studies suggest that vitamin B6 lacks additional value over folic acid (10; 11; 8; 94). One study suggested that pyridoxine alone did not reduce plasma homocysteine (12). Also, it is unclear if lowering homocysteine levels results in reduced cardiovascular morbidity and mortality. In a meta-analysis of B6 supplementation, it lacked effect on nonfatal or fatal myocardial infarctions, stroke, mortality, hospitalization for the first episode of unstable angina, and heart failure hospitalization; however, the trials lacked control for confounding factors (39).
  • Hormonal agentsHormonal agents: The need for vitamin B6 supplementation in women taking birth control pills lacks scientific proof, although some studies show decreased pyridoxine levels in these women (95). In a review of oral contraceptives, the authors reported a decrease in serum pyridoxal 5'-phosphate concentrations, indicating decreased stores of vitamin B6 in women on low-dose oral contraceptives and possible vitamin B6 inadequacy during pregnancy (96).
  • HydrazinesHydrazines: Pyridoxal-5-phosphate plasma concentrations were depressed in children receiving tuberculosis chemotherapy including isoniazid (97). In a case report, pyridoxine was suggested following isoniazid overdose (98). Hydralazine (Apresoline?) may increase pyridoxine requirements (99). Phenelzine may increase pyridoxine requirements (100).
  • ImmunostimulantsImmunostimulants: Vitamin B6 is considered to be important for immune system function, such as for production of antibodies (101). In preliminary research, vitamin B6 had positive effects on immune response, including an increase in the number of T lymphocyte, T helper, and T suppressor cells (102).
  • ImmunosuppressantsImmunosuppressants: Vitamin B6 is considered to be important for immune system function, such as for production of antibodies (101). In preliminary study, vitamin B6 had positive effects on immune response, including an increase in the number of T lymphocyte, T helper, and T suppressor cells (102).
  • Ion exchange phosphate binding resinsIon exchange phosphate binding resins: In human research, vitamin B6 status in hemodialysis users was reduced with erythropoietin-stimulating agents and ion exchange phosphate-binding resins; consequently, supplementation is recommended (89).
  • MagnesiumMagnesium: Pyridoxine alone, or taken with magnesium, may decrease urinary oxalate levels, which may contribute to a certain type of kidney stone (103). Higher pyridoxine intake has been associated with decreased risk of kidney stone formation in women but not in men with no history of stone formation (104). In clinical research, vitamin B6 in combination with magnesium was effective for significant reductions in premenstrual anxiety (78).
  • Neurologic agentsNeurologic agents: Preliminary results indicate that high doses of vitamin B6 may be useful additions to the available treatments for acute neuroleptic-induced akathisia (105; 106). However, reversible neuropathy has been reported at doses of 200mg and higher (37).
  • Osteoporosis drugsOsteoporosis drugs: In human research, B vitamins, including vitamin B6, did not appear to affect bone turnover (107; 108; 109).
  • Parkinson's agentsParkinson's agents: Pyridoxine enhances the metabolism of levodopa, reducing its antiparkinsonism effects. However, the use of carbidopa and levodopa (Sinemet?) may avoid this interaction, as carbidopa may reduce pyridoxine levels (34; 35).
  • Penicillamine (Cuprimine?, Depen?)Penicillamine (Cuprimine?, Depen?): According to secondary sources, penicillamine may reduce plasma levels of vitamin B6.
  • PhenobarbitalPhenobarbital: According to secondary sources, pyridoxine may reduce plasma levels of phenobarbital (Luminal?).
  • PhenytoinPhenytoin: According to secondary sources, pyridoxine may reduce plasma levels of phenytoin (Dilantin?).
  • Photosensitizing agentsPhotosensitizing agents: According to secondary sources, information is conflicting as to whether pyridoxine exacerbates or protects against amiodarone (Cordarone?)-induced photosensitivity.
  • Renal agentsRenal agents: Pyridoxine alone, or taken with magnesium, may decrease urinary oxalate levels, which may contribute to a certain type of kidney stone (103). Higher pyridoxine intake has been associated with decreased risk of kidney stone formation in women but not in men with no history of stone formation (104).

    • Vitamin B6/Herb/Supplement Interactions:

  • Alzheimer's agentsAlzheimer's agents: Epidemiological studies suggest an association between low blood folate and increased prevalence of poor test performance in the global cognitive domain and Alzheimer's disease; this result was lacking with vitamin B6 (77; 47).
  • AntiasthmaticsAntiasthmatics: Theophylline, a prescription drug used to help manage asthma, has been shown to lower pyridoxine levels (79; 80).
  • AntibacterialsAntibacterials: According to secondary sources, destruction of gastrointestinal flora may reduce the production of vitamin B6.
  • Anticoagulants and antiplateletsAnticoagulants and antiplatelets: In a clinical trial, persistent bleeding was reported in one subject (30).
  • AntidepressantsAntidepressants: Preliminary hypotheses suggest that because pyridoxine increases serotonin and GABA levels in the blood, it may benefit people in dysphoric mental states (81). Higher blood levels of homocysteine are associated with increased depression in later life (82); taking pyridoxine supplements in combination with other B vitamins (mainly folic acid) has been shown to be effective for lowering homocysteine levels (6; 7; 8; 9). In human research, a combination of folic acid, vitamin B12, and vitamin B6 was no better than placebo with respect to symptoms of depression in older men (83).
  • AntiemeticsAntiemetics: In clinical research, vitamin B6 supplementation had antinausea effects of similar efficiency to ginger in the first trimester of pregnancy (31).
  • AntineoplasticsAntineoplastics: There are epidemiological data supporting the claim that vitamin B6 lowers the risk of colon cancer (84; 85). Supplementation with a combination of folic acid, vitamin B6, and vitamin B12 lacked an effect on the risk of breast cancer (86). There is evidence that male smokers with higher serum levels of pyridoxine may have a lower risk of lung cancer (87).
  • Cytochrome P450-modifying agentsCytochrome P450-modifying agents: According to secondary sources, vitamin B6 may interact with cytochrome P450 2D6 inhibitors.
  • Dermatologic agentsDermatologic agents: According to secondary sources, acne, allergic reactions, and photosensitivity have been reported. In clinical research, skin rash leading to trial withdrawal was reported with vitamin B6 supplementation (50). In human research on B6 supplementation for atopic eczema, three participants reported eczema flare-up that was caused by bacterial infection (60). A case report of a girl aged 17 years described sudden onset of rosacea fulminans with ingestion of high-dose vitamin B daily; it resolved after discontinuation of the supplement and introduction of a therapeutic regimen of isotretinoin and methylprednisolone (66). According to a systematic review, vitamin B6 lacked an effect on symptoms of eczema based on patient or parent ratings (60).
  • Erythropoietin stimulating agentsErythropoietin stimulating agents: In human research, vitamin B6 status in hemodialysis users was reduced with erythropoietin-stimulating agents and ion exchange phosphate-binding resins; consequently, supplementation is recommended (89).
  • GalactagoguesGalactagogues: Clinical studies of pyridoxine used to suppress lactation have yielded mixed results (91; 92). In a meta-analysis, compared to placebo or bromocriptine, treatment with vitamin B6 lacked a statistically significant difference in regard to the failure to attain suppression of lactation at or within seven days after childbirth (50).
  • Homocysteine-lowering agentsHomocysteine-lowering agents: Taking pyridoxine supplements in combination with other B vitamins (mainly folic acid) has been shown to be effective for lowering homocysteine levels (6; 7; 8; 93). However, some studies suggest that vitamin B6 lacks additional value over folic acid (10; 11; 8; 94). One study suggested that pyridoxine alone did not reduce plasma homocysteine (12). Also, it is not clear if lowering homocysteine levels results in reduced cardiovascular morbidity and mortality. In a meta-analysis of B6 supplementation, it lacked effect on nonfatal or fatal myocardial infarctions, stroke, mortality, hospitalization for the first episode of unstable angina, and heart failure hospitalization; however, the trials lacked control for confounding factors (39).
  • Hormonal agentsHormonal agents: The need for vitamin B6 supplementation in women taking birth control pills lacks scientific proof, although some studies show decreased pyridoxine levels in these women (95). In a review of oral contraceptives, the authors reported a decrease in serum pyridoxal 5'-phosphate concentrations, indicating decreased stores of vitamin B6 in women on low-dose oral contraceptives and possible vitamin B6 inadequacy during pregnancy (96).
  • HypoglycemicsHypoglycemics: In human research, 100mg of pyridoxine daily improved glucose metabolism in gestational diabetes (32; 33).
  • HypotensivesHypotensives: In hypertensive rats, vitamin B6 supplementation had hypotensive effects (27; 28). In hypertensive patients, vitamin B6 (5mg/kg daily) reduced systolic and diastolic blood pressure (49).
  • ImmunomodulatorsImmunomodulators: Vitamin B6 is considered to be important for immune system function, such as for production of antibodies (101). In preliminary research, vitamin B6 had positive effects on immune response, including an increase in the number of T lymphocyte, T helper, and T suppressor cells (102).
  • Ion exchange phosphate binding resinsIon exchange phosphate binding resins: In human research, vitamin B6 status was reduced with erythropoietin-stimulating agents and ion exchange phosphate-binding resins in hemodialysis users; consequently, supplementation is recommended (89).
  • MagnesiumMagnesium: Pyridoxine alone, or taken with magnesium, may decrease urinary oxalate levels, which may contribute to a certain type of kidney stone (103). Higher pyridoxine intake has been associated with decreased risk of kidney stone formation in women but not in men with no history of stone formation (104). In clinical research, vitamin B6 in combination with magnesium was effective for significant reductions in premenstrual anxiety (78).
  • Neurologic agentsNeurologic agents: Preliminary results indicate that high doses of vitamin B6 may be useful additions to the available treatments for acute neuroleptic-induced akathisia (105; 106). Reversible neuropathy has been reported at doses of 200mg and higher (37).
  • Omega-3 fatty acidsOmega-3 fatty acids: According to a review, B vitamins and omega-3 fatty acids have the potential for synergistic protective effects with respect to cardiovascular disease (110).
  • Osteoporosis agentsOsteoporosis agents: In human research, B vitamins, including vitamin B6, lacked an effect on bone turnover (107; 108; 109).
  • Parkinson's agentsParkinson's agents: Pyridoxine enhances the metabolism of levodopa, reducing its antiparkinsonism effects. However, the use of carbidopa and levodopa (Sinemet?) may avoid this interaction, as carbidopa may reduce pyridoxine levels (34; 35).
  • Photosensitizing agentsPhotosensitizing agents: According to secondary sources, information is conflicting as to whether pyridoxine exacerbates or protects against amiodarone (Cordarone?)-induced photosensitivity.
  • Renal agentsRenal agents: Pyridoxine alone, or taken with magnesium, may decrease urinary oxalate levels, which may contribute to a certain type of kidney stone (103). Higher pyridoxine intake has been associated with decreased risk of kidney stone formation in women but not in men with no history of stone formation (104).
  • SedativesSedatives: In clinical research, vitamin B6 in combination with magnesium was effective for significant reductions in premenstrual anxiety (78).

    • Vitamin B6/Food Interactions:

  • Insufficient available evidence.

    • Vitamin B6/Lab Interactions:

  • Birth weightBirth weight: In human research, a meta-analysis of birth outcomes revealed that treatment with vitamin B6 resulted in a significant beneficial effect on birthweight (42).
  • Blood glucoseBlood glucose: In human research, 100mg of pyridoxine daily improved glucose metabolism in gestational diabetes (32; 33).
  • Blood pressureBlood pressure: In hypertensive rats, vitamin B6 supplementation had hypotensive effects (27; 28). In hypertensive patients, vitamin B6 (5mg/kg daily) reduced systolic and diastolic blood pressure (49).
  • Breast milk productionBreast milk production: Clinical studies of pyridoxine used to suppress lactation have yielded mixed results (91; 92). In a meta-analysis, compared to placebo or bromocriptine, treatment with pyridoxine lacked a statistically significant difference in regard to the failure to attain suppression of lactation at or within seven days after childbirth (50).
  • Coagulation panelCoagulation panel: In a clinical trial, persistent bleeding was reported in one subject (30).
  • Erythropoietin stimulating agentsErythropoietin stimulating agents: In human research, vitamin B6 status in hemodialysis users was reduced with erythropoietin-stimulating agents and ion exchange phosphate-binding resins; consequently, supplementation is recommended (89).
  • Immune panelImmune panel: Vitamin B6 is considered to be important for immune system function, such as for production of antibodies (101). In preliminary research, vitamin B6 had positive effects on immune response, including an increase in the number of T lymphocyte, T helper, and T suppressor cells (102).
  • Ion exchange phosphate binding resinsIon exchange phosphate binding resins: In human research, vitamin B6 status in hemodialysis users was reduced with erythropoietin-stimulating agents and ion exchange phosphate-binding resins; consequently, supplementation is recommended (89).
  • Oxalate levelsOxalate levels: Pyridoxine alone, or taken with magnesium, may decrease urinary oxalate levels, which may contribute to a certain type of kidney stone (103). Higher pyridoxine intake has been associated with decreased risk of kidney stone formation in women but not in men with no history of stone formation (104).
  • Plasma amino acidsPlasma amino acids: In humans, vitamin B6 decreased plasma levels of the amino acids tyrosine and methionine during endurance exercise (111).
  • Plasma free fatty acidsPlasma free fatty acids: In humans, vitamin B6 decreased plasma levels of free fatty acids during endurance exercise (111).
  • Plasma homocysteinePlasma homocysteine: Taking pyridoxine supplements in combination with other B vitamins (mainly folic acid) has been shown to be effective for lowering homocysteine levels (6; 7; 8; 93). However, some studies suggest that vitamin B6 lacks additional value over folic acid (10; 11; 8; 94). One study suggested that pyridoxine alone did not reduce plasma homocysteine (12).
  • Plasma pyridoxal-5'-phosphate (PLP)Plasma pyridoxal-5'-phosphate (PLP): In human research, treatment with vitamin B6 resulted in significantly increased maternal plasma, cord, and infant plasma PLP compared to placebo treatment (42).