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pyridoxine

Vitamin B6 · Vitamin

Vitamin B6VitaminATC A11HA02
CDSCO approvedATC A11HA02
EXCRETION
—
not curated
INTERACTIONS
1 major
SEVERE in our sources
PREGNANCY
A
FDA category + note
Top interactionssee all 6 →
  • IsoniazidSevereTextbookKDT 7e · p915

Mechanism

Not yet extracted

Indications

hereditary sideroblastic anemiaacquired sideroblastic anemiasideroblastic anemias associated with antituberculosis drugs isoniazid and pyrazinamideNausea and vomiting of pregnancySideroblastic anaemia associated with isoniazid and pyrazinamide therapyProphylaxis of isoniazid neurotoxicityTreatment of isoniazid neurotoxicityProphylaxis of vitamin B6 deficiency (in alcoholics, infants, and patients with deficiencies of other B vitamins)Prevention and treatment of isoniazid, hydralazine, and cycloserine-induced neurological disturbancesTreatment of acute isoniazid poisoningTreatment of mental symptoms in women on oral contraceptivesPyridoxine responsive anaemia (due to defective haeme synthesis)Homocystinuria (rare genetic disorder)Convulsions in infants and children

Dosing

Adult
For sideroblastic anemias associated with isoniazid and pyrazinamide: 50 mg/day. For idiopathic acquired sideroblastic anemia: 50 to 500 mg/day (oral); refractory cases may respond to parenteral pyridoxal phosphate.
Pediatric
Not mentioned in text, omitted as per instructions to not interpolate.

Pharmacokinetics

Peak effect
Well absorbed
Half-life
2 to 3 weeks
Metabolism
Not specified
Excretion
Oxidized in the body and excreted as pyridoxic acid.

Side effects

Serious
  • Sensory neuropathy (with mega doses of 0.2–2.0 g/day)
  • Suppression of lactation (in nonsuckling postpartal women given high doses)

Pregnancy & lactation

Pregnancy

A

Drug interactions

Isoniazid
Severe
Textbook

Induces a pyridoxine deficiency state, leading to neurological disturbances such as peripheral neuritis.

Administer pyridoxine (10–50 mg/day) prophylactically to prevent, and therapeutically to treat, isoniazid-induced neurological disturbances. Massive doses (in grams) may be used for acute isoniazid poisoning.

Source: KDT 7e · p915

Cycloserine
Moderate
Textbook

Can lead to pyridoxine deficiency and associated neurological disturbances.

Administer pyridoxine (10–50 mg/day) to prevent and treat cycloserine-induced neurological disturbances.

Source: KDT 7e · p916

Hydralazine
Moderate
Textbook

Can lead to pyridoxine deficiency and associated neurological disturbances.

Administer pyridoxine (10–50 mg/day) to prevent and treat hydralazine-induced neurological disturbances.

Source: KDT 7e · p916

Penicillamine
Moderate
Textbook

Can lead to pyridoxine deficiency.

Consider pyridoxine supplementation in patients receiving penicillamine to prevent deficiency.

Source: KDT 7e · p916

Levodopa
Moderate
Database

The effectiveness of levodopa in controlling Parkinson's disease is decreased.

If pyridoxine is given to counteract sideroblastic abnormality, it will decrease the effectiveness of levodopa. Consider this clinical effect.

Source: DDInter

Oral Contraceptives
Mild
Textbook

May cause mental symptoms.

Consider pyridoxine supplementation (50 mg daily) to treat mental symptoms in women using oral contraceptives, if related to pyridoxine deficiency.

Source: KDT 7e · p916

6 additional low-confidence interactions hidden — those rows lack a documented mechanism or management plan in our sources.

Related guidelines

Iron deficiency anaemia in pregnancy
ICMR · Obstetrics & Gynaecology · 2022
Iron deficiency anaemia in pregnancy
FOGSI · Obstetrics & Gynaecology · 2017
Iron deficiency anaemia in adults
ICMR · Hematology · 2023
Hypertensive disorders of pregnancy
FOGSI · Obstetrics & Gynaecology · 2019
Hypertensive disorders of pregnancy
ACOG · Obstetrics & Gynaecology · 2020

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Sources: KD Tripathi 7e, Goodman & Gilman 14e·Verified: 2026-05-10 · House clinical team