Treatment of latent tuberculosis
International guidelines recommend a number of regimens for latent TB that are likely to be equivalent in efficacy. The choice of regimen for a patient should be based on: age-related risk of hepatotoxicity from isoniazid, potential for drug interactions with rifamycins (eg rifampicin interacts with the oral contraceptive pill), duration of therapy, likelihood of drug resistance and drug availability. Regimens include:
1 isoniazid (adult and child) 10 mg/kg up to 300 mg orally, daily for 9 months123. For dosage adjustment in adults with kidney impairment, see isoniazid dosage adjustment tuberculosis, latent isoniazid
OR
1 rifampicin 10 mg/kg up to 600 mg (child younger than 14 years and more than 50 kg: 600 mg; child younger than 14 years and less than 50 kg: 15 mg/kg up to 450 mg) orally, daily for 4 months. For dosage adjustment in adults with kidney impairment, see rifampicin dosage adjustment tuberculosis, latent rifampicin
OR
1 rifampicin 10 mg/kg up to 600 mg (child younger than 14 years and more than 50 kg: 600 mg; child younger than 14 years and less than 50 kg: 15 mg/kg up to 450 mg) orally, daily for 3 months. For dosage adjustment in adults with kidney impairment, see rifampicin dosage adjustment rifampicin
PLUS
isoniazid (adult and child) 10 mg/kg up to 300 mg orally, daily for 3 months23. For dosage adjustment in adults with kidney impairment, see isoniazid dosage adjustment isoniazid isoniazid
OR
1 rifapentine orally, weekly for 3 months4. For dosage adjustment in adults with kidney impairment, see rifapentine dosage adjustment tuberculosis, latent rifapentine
adult and child 12 years or older and more than 50 kg: 900 mg
adult and child 12 years or older and 32.1 to 50 kg: 750 mg
child age 2 to 11 years: 10 to 14 kg: 300 mg; 14.1 to 25 kg: 450 mg; 25.1 to 32 kg: 600 mg; 32.1 to 50 kg: 750 mg; more than 50 kg: 900 mg
PLUS
isoniazid 15 mg/kg up to 900 mg (child age 2 to 11 years: 25 mg/kg up to 900 mg) orally, weekly for 3 months235. isoniazid For dosage adjustment in adults with kidney impairment, see isoniazid dosage adjustment.
Monitor liver function for patients being treated for latent TB; for example, at 2 and 4 weeks after starting therapy, or more frequently if there are risk factors for or pre-existing liver disease (see Monitoring tuberculosis therapy). Educate patients about the symptoms of hepatitis.
People who have been treated for latent TB can acquire TB again (eg migrants who return to visit family and friends in countries where TB is endemic).