If you have latent TB infection—that is, a positive PPD test without any signs or symptoms of active TB—your doctor will probably prescribe one of these two possible treatments:
Treatments for latent TB infection (LTBI)
Isoniazid (Nydrazid): One of the most effective antibiotics used to control TB. It can cause liver problems and tingling/numbness of the hands and/or feet (peripheral neuropathy). It is usually taken with a second drug, pyridoxine, to help prevent peripheral neuropathy. You will probably take this drug (300 mg), every day, for nine months. Alternatively, isoniazid can be given twice a week for a total of nine months. However, if the twice-weekly dosing schedule is used, you will need to report to a clinic to receive your medication to make sure that you are not missing any of your doses. This is called directly observed therapy, or DOT. Some people take isoniazid for only six months. However, this is not recommended for people infected with HIV.
It is very important that you take your isoniazid and pyridoxine exactly as your doctor tells you to and that you continue taking these medications until your doctor tells you that it is time to stop. This is necessary to prevent the bacteria from becoming resistant to isoniazid. If the bacteria becomes resistant to isoniazid, you can develop active TB that is harder to treat.
Rifampin (Rifadin): Only needs to be taken once a day for a total of four months. However, there are a number of concerns when it comes to using this drug in combination with anti-HIV medications. Rifampin can interact with many protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs). Thus, to be on the safe side, it is generally recommended that HIV-positive people who are taking either a PI or NNRTI follow the nine-month isoniazid treatment option (discussed above). The rifampin option is best for people who will have a hard time sticking to the strict nine-month isoniazid course and are not taking either a PI or a NNRTI. If you are prescribed rifampin, it is very important that you take it exactly as your doctor tells you to and that you continue taking this medication until your doctor tells you that it is time to stop. This is necessary to prevent the bacteria from becoming resistant to these two drugs. If the bacteria becomes resistant to the drugs, you can develop active TB that is harder to treat.
Two potential side effects of TB therapy are liver damage (hepatitis) and damage to the nerves in the feet, hands and face, called neuroapthy. It is recommended that people being treated for latent tuberculosis be monitored at least once every month to monitor adherence to treatment and for side effects. People who are exposed to TB that is suspected to be resistant to isoniazid or rifampin may need to receive additional medication. In these cases it is recommended that a person work with local public health authorities and an expert on multi-drug resistant TB to determine the best alternative regimens.
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