Tuberculosis (TB) is a contagious bacterial infection that involves the lungs, but may spread to other organs.
You may have a TB infection but no active disease or symptoms. This means the TB bacteria remain inactive (dormant) in a small area of your lungs. This type of infection may be present for years and is called latent TB. With latent TB:
You cannot spread TB to other people.
In some people, the bacteria can become active. If this happens, you may become sick or you can pass the TB germs to someone else.
Even though you do not feel sick, you need to take medicines for TB for 6 to 9 months. This is the only way to make sure all of the TB bacteria in your body are killed.
When you have active TB, you may feel sick or have a cough, lose weight, feel tired, or have a fever or night sweats. In this case:
You can pass TB to people around you. This includes people you live, work, or come in close contact with.
You need to take medicines for TB for at least 6 months to rid your body of the TB bacteria. You should begin to feel better within a month of starting medicines.
For the first 2 to 4 weeks after starting the medicines, you may need to stay home to avoid spreading TB to others. Ask your doctor when it is OK to be around others.
Your doctor is required by law to report your case to the local public health department.
Ask your doctor whether others with whom you work or live should be tested for TB.
How to Take the Medicines
TB germs die very slowly. You need to take several different pills at different times of the day for 6 months or longer. The only way to get rid of the germs is to take your TB medicines the way your doctor has instructed. This means taking all of your medicines every day.
If you do not take your TB medicines the right way, or stop taking the medicines early:
Your TB infection may become worse.
Your infection may become harder to treat. The drugs you are taking may no longer work. This is called drug-resistant TB.
You may need to take other medicines with more side effects and less ability to remove the infection.
You may spread the infection to others.
If your doctor is worried that you may not be taking all the medicines as directed, they may arrange to have someone meet with you every day or a few times a week to watch you take your TB drugs. This is called directly observed therapy.
Side Effects and Other Problems
Women who may be pregnant, who are pregnant, or who are breastfeeding should talk to their doctors before taking these medicines. If you are using birth control pills, ask your doctor if your TB medicines can make birth control pills not work as well.
Most people do not have very bad side effects from TB medicines. Problems to watch out for and tell your doctor about include:
Bruising or easy bleeding
Less or no appetite
Tingling or aches in your toes, fingers, or around your mouth
Upset stomach, nausea or vomiting, and stomach cramps or pain
Yellow skin or eyes
Call your doctor if you have:
Any of the side effects listed above
New symptoms of active TB, such as cough, fever or night sweats, shortness of breath, or pain in the chest
Hopewell PC, Kato-Maeda M. Tuberculosis. In: Mason RJ, Murray JF, Broaddus VC, et al., eds. Murray and Nadel's Textbook of Respiratory Medicine. 5th ed. Philadelphia, PA: Elsevier Saunders; 2010:chap 34.
Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.