Many people who have latent tuberculosis never develop active TB. However, some people who have latent TB infection are more likely to develop active TB than others. These people are at high risk for active tuberculosis. They include:
- People with HIV infection
- People who became infected with TB bacteria in the last 2 years
- Babies and young children
- People who inject illegal drugs
- People who are sick with other diseases that weaken the immune system
- Elderly people
- People who were not treated correctly for TB in the past.
(Click Causes of Tuberculosis to learn about other tuberculosis risk factors.)
If you have latent tuberculosis (a positive TB skin test reaction or positive blood test) and you are in one of these high-risk groups, you need to take medicine to keep from developing active tuberculosis. This is called treatment for latent tuberculosis. There are several latent tuberculosis treatment options. You and your healthcare provider must decide which treatment is best for you.
The medicine commonly used for the treatment of latent tuberculosis is called isoniazid (INH). INH kills the TB bacteria that are in the body. If you take your medicine as instructed by your doctor or nurse, it can keep you from developing active tuberculosis. Treatment for latent TB in children and people with HIV infection may need to be longer.
Because there are fewer bacteria in a person with latent tuberculosis, treatment is much easier. Usually, only one drug is needed to treat latent tuberculosis. A person with active tuberculosis has a large amount of TB bacteria in the body. Several drugs are needed to treat active tuberculosis.
Sometimes people are given treatment for latent tuberculosis even if their tuberculosis test is not positive. This is often done with infants, children, and HIV-infected people who have recently spent time with someone with active tuberculosis. This is because they are at very high risk of developing active tuberculosis soon after they become infected with TB bacteria.
If you have latent tuberculosis, it is important that you take all your tuberculosis medication as prescribed. If you start taking INH, you will need to see your doctor or nurse on a regular schedule. He or she will check on how you are doing.
Some people have serious side effects from INH. If you have any of the following side effects, call your doctor or nurse right away:
- No appetite
- Yellowish skin or eyes
- Fever for 3 or more days
- Abdominal pain
- Tingling in the fingers and toes.
Drinking alcoholic beverages (wine, beer, and liquor) while taking INH can be dangerous. Check with your doctor or nurse for more information.