If latent tuberculosis is suspected (based on tuberculin skin tests, interferon-gamma release assays, high-risk exposure, personal history of active tuberculosis, or residence in a region with high tuberculosis prevalence), regardless of CD4 count, patients should be given isoniazid 5 mg / kg (up to 300 mg) orally once / day plus pyridoxine (vitamin B6) 10 to 25 mg orally once / day for 9 months to prevent reactivation.