Many people who have TB infection never develop TB disease. But some people who have TB infection are more likely to develop TB disease than others. These people are at high risk for TB disease. They include:
- People with HIV infection
- People in close contact with a person who has infectious TB
- People who became infected with TB bacteria in the last two years
- Babies and young children
- People who inject drugs
- People sick with other diseases that weaken the immune system
- The elderly
If you have TB infection (a positive skin test reaction) and you are in one of these high-risk groups, you may need to take medicine to keep from developing TB disease. This kind of treatment is called Preventive Therapy. Also, if you are younger than 35 and you have TB infection, you may benefit from preventive therapy even if you are not in a high-risk group.
People who have TB infection but do not receive preventive therapy need to know the symptoms of TB. If symptoms of TB disease develop later on, see a doctor right away.
The medicine usually used for preventive therapy is a drug called isoniazid or INH. INH kills the inactive TB bacteria in the body. If you take your medicine as prescribed, preventative therapy will keep you from ever developing TB disease from this infection.
Most people must take INH for at least 6 months. Children and people with HIV infection may need to take INH for a longer time.
Sometimes people are given preventive therapy even if their skin test reaction is not positive. This is often done with infants, children, and HIV-infected people who have recently spent time with someone with infectious TB disease. This is because they are at a very high risk of developing serious TB disease soon after they become infected with TB bacteria.
It is important that you take all the pills prescribed for you so that your preventive therapy is effective. If you start taking INH, you will need to see your doctor or nurse on a regular schedule. Very few people have serious side effects from INH. However, if you have any of the following side effects, call your doctor or your nurse promptly:
- No appetite
- Nausea
- Vomiting
- Yellowish skin or eyes
- Fever for more than three days
- Abdominal pain
- Tingling in the fingers and toes.
All drugs to treat TB are available without charge to the patient through the DSHS TB Elimination Division.