Vitamin B6 Dosing for Nausea

Recommended Dosing Algorithm

The American College of Obstetricians and Gynecologists recommends starting with 10-25 mg of vitamin B6 orally every 8 hours for pregnancy-related nausea, which can be titrated based on symptom severity and response 1
For initial therapy, start with 10 mg orally every 8 hours for mild to moderate symptoms, and increase to 25 mg every 8 hours if inadequate response after 24-48 hours, with a maximum recommended dose of 25 mg three times daily (75 mg total daily) 1
The American College of Obstetricians and Gynecologists recommends adding doxylamine to vitamin B6 for combination therapy if monotherapy is insufficient 1

The recommended daily intake for adults is 1.3-1.7 mg/day, with an upper tolerable limit of 100 mg/day 2
Doses used for pregnancy nausea (30-75 mg/day) are well below the toxicity threshold 1
Chronic intake exceeding 100 mg/day can cause sensory neuropathy 3
Toxicity primarily occurs with prolonged use of doses >100 mg/day, not with the therapeutic doses recommended for nausea 4

The Motherisk Pregnancy-Unique Quantification of Emesis (PUQE) score can objectively assess severity: mild (≤6), moderate (7-12), or severe (≥13) 1
Reassess symptoms after 3-4 days of therapy to determine if dose escalation or combination therapy is needed 1