From the Guidelines
The standard INH protocol for latent tuberculosis infection treatment involves taking 300 mg of isoniazid daily for 6-9 months, with the 9-month regimen being conditionally recommended for adults and children of all ages, both HIV-negative and HIV-positive, as it provides optimal protection with reduced risk of developing TB disease 1.
Key Considerations
- For HIV-negative adults and children, 6 months of daily isoniazid is strongly recommended, while for HIV-positive adults and children, it is conditionally recommended 1.
- The 9-month regimen is conditionally recommended for adults and children of all ages, both HIV-negative and HIV-positive, due to its potential to reduce the risk of developing TB disease, although it may be associated with hepatotoxicity and discontinuation due to adverse effects 1.
- Isoniazid reduces the risk for developing TB disease in persons with a positive TST, including HIV-negative adults and children, as well as HIV-positive adults and children 1.
Special Populations
- For pregnant, HIV-negative women, isoniazid given daily or twice weekly for 9 or 6 months is recommended, with initiation of therapy not delayed on the basis of pregnancy alone, even during the first trimester, for those at risk for progression of LTBI to disease 1.
- For children and adolescents, isoniazid given either daily or twice weekly for 9 months is the recommended regimen 1.
Monitoring and Adverse Effects
- Monthly monitoring for adverse effects is essential, including liver function tests for those with risk factors for hepatotoxicity 1.
- Pyridoxine (vitamin B6) supplementation at 25-50 mg daily is recommended to prevent peripheral neuropathy, particularly for individuals at higher risk such as pregnant women, diabetics, those with HIV, and people with malnutrition or alcoholism 1.
From the Research
INH Protocol Overview
- The standard treatment for latent tuberculosis infection (LTBI) has been 9 months of daily isoniazid (INH) monotherapy, which has an efficacy of more than 90% if completed properly 2.
- However, INH is associated with serious adverse events, including hepatotoxicity, and has poor acceptance and adherence rates due to its lengthy duration 2.
Alternative Regimens
- A 4-month regimen of rifampin has been shown to be noninferior to 9 months of INH, with a higher rate of treatment completion and better safety 3.
- A 12-dose regimen of once-weekly isoniazid and rifapentine has also been shown to be noninferior to 9 months of daily INH 4.
- Other regimens, such as 3 months of daily isoniazid and rifampin, or 4 months of daily rifampin alone, have also been recommended and used 4.
Recent Updates
- Novel vaccine strategies, host immunity-directed therapies, and ultrashort antimicrobial regimens for TB prevention, such as daily isoniazid plus rifapentine for 1 month, are under evaluation 5.
- The results of ongoing trials comparing the efficacy and effectiveness of different regimens will likely shape future recommendations substantially 2.