Multiple-drug therapy for tuberculosis (TB)
Examples
First-choice medicines:
Generic Name Brand Name ethambutol hydrochloride Etibi isoniazid pyrazinamide rifabutin Mycobutin rifampin Rifadin rifapentine Priftin Second-choice medicines:
Generic Name Brand Name levofloxacin Levaquin moxifloxacin hydrochloride Avelox, Vigamox streptomycin sulfate Combination medications:
Generic Name Brand Name isoniazid plus pyrazinamide plus rifampin Rifater How It Works
These antibiotics kill the bacteria that cause tuberculosis (TB).
Multiple-drug therapy to treat TB means taking several different antibiotics at the same time. This is the first choice of treatment for TB that is growing in your body (active TB disease). Most of these medicines are given as pills. Health Canada and the Canadian Lung Association recommend using one of several combinations of the first-choice medicines to start treatment.1
The standard treatment is to take isoniazid, rifampin, ethambutol, and pyrazinamide for 2 months. Treatment is then continued for at least 4 months with fewer medicines. Also, there are special treatment recommendations for people with HIV and TB, people with drug-resistant TB, children with active TB, and pregnant women with active TB.
Prepared combination medicines, such as Rifater, are usually used when there is a need for fewer numbers of pills, such as when a health professional is not giving each dose of medicine personally. Combining antibiotics into a single pill makes it less likely that you will miss taking any doses. Failure to take a medicine could prolong your treatment and increase your chance of developing drug-resistant TB.
Streptomycin usually is given only to people who cannot take ethambutol.
Isoniazid given alone usually prevents a latent TB infection from turning into active TB disease, which can spread to other people.2 Rifampin also can help prevent latent TB from becoming active TB.
Why It Is Used
Treatment with several medicines makes it more likely that all TB-causing bacteria will be killed. The combination of medicines and the length of treatment may change based on:
- Whether you have latent TB or active TB.
- Whether you are also infected with the human immunodeficiency virus (HIV).
- Whether you are pregnant.
- Your age.
- The results of sensitivity testing, which determine the medicines that can kill the TB bacteria you have.
How Well It Works
Treatment for active TB disease
When multiple-drug therapy combines 4 medications, up to 90% of people have a sputum culture that indicates no infection within 3 months after beginning treatment.3 For people infected with TB bacteria that can be killed by the medicines used for treatment, 98% are permanently cured if they take the medicines exactly as they should.4 The cure rate for people who have TB and HIV is similar to that for people who have only TB.5
It takes at least 6 months of treatment for a cure. It could take longer if doses are missed. It can also take longer if the disease does not respond well to the medication.
Treatment for latent TB infection
For most people who have a latent TB infection, taking isoniazid alone reduces the risk of developing active TB disease by up to 80%.3
Side Effects
Side effects of medications used to treat TB are not common. However, if they occur, they can be severe. Contact your doctor immediately if you are taking isoniazid, rifampin, or pyrazinamide and you develop any of these side effects:
- Loss of appetite, nausea, or vomiting
- Skin rash
- Yellow colour to your skin (jaundice)
- A general feeling of being ill (malaise)
- A fever that lasts for 3 or more days with no obvious cause, such as a cold or the flu
- Tenderness or soreness in your abdomen
Rifampin colours your urine, sputum, sweat, and tears orange-red. This is normal; the colour will go away when you stop taking the medication. However, it will stain your clothing and your contact lenses.
Contact your doctor immediately if you are taking ethambutol and begin to have blurred vision or colour blindness.
Some people are allergic to streptomycin, which can cause nausea, vomiting, dizziness, and, rarely, hearing loss.
See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)
What To Think About
Before and sometimes during treatment with these medications, you may have tests to check your liver.
It is important to take all of the medications during your treatment to ensure the infection is cured, to protect others from TB, and to reduce the risk of a relapse.
A health professional may have to watch you take all doses of your medications. This is called directly observed therapy (DOT), and it helps make sure that people take their medicines exactly as they are supposed to. As a result, cure rates for TB have significantly improved.6 If medication is not taken as prescribed, drug resistance may develop. If this happens, the bacteria become harder to kill.
Taking all of the medications prescribed is especially important for people who have an impaired immune system; they may be at increased risk for relapse because the original infection was never cured.
Some of the medications that are used to treat TB disease are not recommended in certain circumstances. However, they still may be used cautiously.
- Isoniazid is not recommended for people who have acute or unstable liver disease because isoniazid may cause further liver damage.
- Streptomycin and rifapentine are not recommended for pregnant women because they may harm the fetus.
- Ethambutol is not recommended for use with children who are too young to tell whether they are developing vision problems.
A woman can breast-feed her baby during TB treatment without worrying that the medications will harm the baby.
People who have a weakened immune system also are treated with multiple medications (multiple-drug therapy).
Be certain your doctor knows about any other medications you are taking, both prescription and non-prescription. Some of these medications can interact with TB medicines:
- When taken with isoniazid, acetaminophen (for example, Tylenol) can increase the risk of liver damage.
- Rifampin affects the action of many medications, including cyclosporine, dapsone, warfarin, methadone, digoxin, and corticosteroids.
- Rifampin also may reduce the effectiveness of birth control pills. Consider using another method of birth control while you are taking this medicine.
If you must be in the hospital during TB treatment, you will be in a special room that filters the TB bacteria out of the air. This will prevent health care workers and other people in the hospital from getting a TB infection. You probably will not be able to leave the room until you have 3 sputum samples that show you can no longer spread the infection.
If you have active TB, the health department will test people who work or live with you to see if they have a TB infection. If they have TB, they will get treated to prevent the spread of the disease.
It is best to take these medications without food. However, if they upset your stomach, you can take them with food.
Do not drink alcohol during treatment for TB, because it can increase your risk of liver damage.
To help you understand what your medication is for, how to take it, and what side effects to watch for, complete a new medication form
(What is a PDF document?).
Complete the new medication information form (PDF)
| Author: | Maria G. Essig, MS, ELS Merrill Hayden | Last Updated: July 25, 2007 |
| Medical Review: | E. Gregory Thompson, MD - Internal Medicine Alfred A. Lardizabal, MD - Pulmonology and Critical Care Medicine/Tuberculosis Andrew Swan, MD, CCFP, FCFP - Family Medicine | |
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| Topic Contents | |
| Examples | |
| How It Works | |
| Why It Is Used | |
| How Well It Works | |
| Side Effects | |
| What To Think About | |
| References | |