<prompt> Patients on isoniazid which vitamin deficiency is more likely to be seen.Vitamin B9Vitamin B12Vitamin B6Vitamin B3  <response>: Ans. c Vitamin B6Ref. KDT 6th ed. 740-41 For patients who are on isoniazid; peripheral neuropathy is observed in 10-20 of patients given dosages greater than 5 mgkgd but is infrequently seen with the standard 300 mg adult dose. Pyridoxine Vit B6, 25-50 mgd, is recommended for those with conditions predisposing to neuropathy, an adverse effect of isoniazid. NOTE: Isoniazid as a single agent is also indicated for treatment of latent tuberculosis. The dosage is 300 mgd 5 mgkgd or 900 mg twice weekly for 9 months. 