Guidelines for Treatment of Latent Tuberculosis Infection

High-Priority Candidates for Treatment of LTBI

Positive QFT (greater than 0.35 I.U.)

TST ≥5 mm

  • HIV-positive persons
  • Recent contacts of person with infectious TB
  • Persons with fibrotic changes on CXR suggestive of previous TB; or inadequate treatment
  • Persons with organ transplants or immunosuppression therapy

TST ≥10 mm

  • Recent arrivals (<five years) from endemic areas
  • Substance abusers
  • Residents/employees of health care, correctional or long-term care facilities
  • Children and adolescents exposed to high-risk adults
  • Persons at high-risk for certain medical conditions

Conditions that Increase the Risk of TB Disease

  • Diabetes mellitus
  • HIV infection
  • Substance abuse
  • TST converter (≥10mm increase in TST in past 24 months)
  • Prolonged corticosteroid therapy or other immunosuppressive therapy
  • End-stage renal disease
  • CXR findings suggestive of previous TB in persons inadequately treated
  • Cancer of head and neck
  • Hematologic and reticuloendothelial disease
  • Intestinal bypass or gastrectomy
  • Chronic malabsorption syndromes
  • Silicosis
  • Low body weight (10% or more below ideal)
  • Recent contact to person with infectious TB
  • Infants and children <5years with known positive TST

Possible Contraindications

  • Persons at high risk for adverse reactions to isoniazid (INH)
  • Persons who cannot tolerate INH
  • Persons likely to be infected with drug-resistant M. tuberculosis
  • Persons who are highly unlikely to complete a course of therapy

Use Caution When Prescribing Treatment for LTBI in Persons Who:

  • Abuse alcohol
  • Are on hormonal contraceptives
  • Are pregnant
  • Inject drugs
  • Currently use other medications that may interact
  • Have chronic liver disease
  • Have/are at risk for peripheral neuropathy
  • Have a history of adverse reactions to LTBI medications

Centers for Disease Control and Prevention (CDC) Preferred Regimen



  • Adults need nine months of therapy; 5 mg/kg/day, not to exceed 300 mg/day
  • Children need nine months of therapy; 10-15 mg/kg/day, not to exceed 300 mg/day

Please consider pyridoxine 50 mg daily to reduce symptoms of vitamin B deficiency.

Alternate Regimens



  • Adults need four months of therapy: RIF—10 mg/kg/day, not to exceed 600 mg/day
  • Children need four months of therapy: RIF—10 to 20 mg/kg/day, not to exceed 600 mg/day


Patient Education

  • Will need monthly visits (all regimens)
  • Educate on signs and symptoms of hepatitis
  • Rifampin discolors urine
  • Rifampin may interfere with anticoagulant therapy, reduces the efficacy of hormonal contraceptives
  • Educate on symptoms of neurotoxicity

Monitor Monthly

Monitor patient on treatment for LTBI for the following:

  • Adherence to the prescribed regimen
  • Signs and symptoms of hepatitis
  • Symptoms of neurotoxicity

Dispense no more than one month supply of medication at one time.

Call if you have questions:

Communicable Disease Control (253) 798-6410, press 0

Confidential Fax (253) 798-7666